/*
 * Copyright (c) 2014 Qualcomm Atheros, 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"

/* Set/change channels.  If the channel is really being changed, it's done
 * by reseting the chip.  To accomplish this we must first cleanup any pending
 * DMA, then restart stuff.
 */
static int ath_set_channel(struct ath_softc *sc)
{
        struct ath_hw *ah = sc->sc_ah;
        struct ath_common *common = ath9k_hw_common(ah);
        struct ieee80211_hw *hw = sc->hw;
        struct ath9k_channel *hchan;
        struct cfg80211_chan_def *chandef = &sc->cur_chan->chandef;
        struct ieee80211_channel *chan = chandef->chan;
        int pos = chan->hw_value;
        int old_pos = -1;
        int r;

        if (test_bit(ATH_OP_INVALID, &common->op_flags))
                return -EIO;

        if (ah->curchan)
                old_pos = ah->curchan - &ah->channels[0];

        ath_dbg(common, CONFIG, "Set channel: %d MHz width: %d\n",
                chan->center_freq, chandef->width);

        /* update survey stats for the old channel before switching */
        spin_lock_bh(&common->cc_lock);
        ath_update_survey_stats(sc);
        spin_unlock_bh(&common->cc_lock);

        ath9k_cmn_get_channel(hw, ah, chandef);

        /* If the operating channel changes, change the survey in-use flags
         * along with it.
         * Reset the survey data for the new channel, unless we're switching
         * back to the operating channel from an off-channel operation.
         */
        if (!sc->cur_chan->offchannel && sc->cur_survey != &sc->survey[pos]) {
                if (sc->cur_survey)
                        sc->cur_survey->filled &= ~SURVEY_INFO_IN_USE;

                sc->cur_survey = &sc->survey[pos];

                memset(sc->cur_survey, 0, sizeof(struct survey_info));
                sc->cur_survey->filled |= SURVEY_INFO_IN_USE;
        } else if (!(sc->survey[pos].filled & SURVEY_INFO_IN_USE)) {
                memset(&sc->survey[pos], 0, sizeof(struct survey_info));
        }

        hchan = &sc->sc_ah->channels[pos];
        r = ath_reset(sc, hchan);
        if (r)
                return r;

        /* The most recent snapshot of channel->noisefloor for the old
         * channel is only available after the hardware reset. Copy it to
         * the survey stats now.
         */
        if (old_pos >= 0)
                ath_update_survey_nf(sc, old_pos);

        /* Enable radar pulse detection if on a DFS channel. Spectral
         * scanning and radar detection can not be used concurrently.
         */
        if (hw->conf.radar_enabled) {
                u32 rxfilter;

                rxfilter = ath9k_hw_getrxfilter(ah);
                rxfilter |= ATH9K_RX_FILTER_PHYRADAR |
                                ATH9K_RX_FILTER_PHYERR;
                ath9k_hw_setrxfilter(ah, rxfilter);
                ath_dbg(common, DFS, "DFS enabled at freq %d\n",
                        chan->center_freq);
        } else {
                /* perform spectral scan if requested. */
                if (test_bit(ATH_OP_SCANNING, &common->op_flags) &&
                        sc->spec_priv.spectral_mode == SPECTRAL_CHANSCAN)
                        ath9k_cmn_spectral_scan_trigger(common, &sc->spec_priv);
        }

        return 0;
}

void ath_chanctx_init(struct ath_softc *sc)
{
        struct ath_chanctx *ctx;
        struct ath_common *common = ath9k_hw_common(sc->sc_ah);
        struct ieee80211_supported_band *sband;
        struct ieee80211_channel *chan;
        int i, j;

        sband = &common->sbands[NL80211_BAND_2GHZ];
        if (!sband->n_channels)
                sband = &common->sbands[NL80211_BAND_5GHZ];

        chan = &sband->channels[0];
        for (i = 0; i < ATH9K_NUM_CHANCTX; i++) {
                ctx = &sc->chanctx[i];
                cfg80211_chandef_create(&ctx->chandef, chan, NL80211_CHAN_HT20);
                INIT_LIST_HEAD(&ctx->vifs);
                ctx->txpower = ATH_TXPOWER_MAX;
                ctx->flush_timeout = HZ / 5; /* 200ms */
                for (j = 0; j < ARRAY_SIZE(ctx->acq); j++) {
                        INIT_LIST_HEAD(&ctx->acq[j].acq_new);
                        INIT_LIST_HEAD(&ctx->acq[j].acq_old);
                        spin_lock_init(&ctx->acq[j].lock);
                }
        }
}

void ath_chanctx_set_channel(struct ath_softc *sc, struct ath_chanctx *ctx,
                             struct cfg80211_chan_def *chandef)
{
        struct ath_common *common = ath9k_hw_common(sc->sc_ah);
        bool cur_chan;

        spin_lock_bh(&sc->chan_lock);
        if (chandef)
                memcpy(&ctx->chandef, chandef, sizeof(*chandef));
        cur_chan = sc->cur_chan == ctx;
        spin_unlock_bh(&sc->chan_lock);

        if (!cur_chan) {
                ath_dbg(common, CHAN_CTX,
                        "Current context differs from the new context\n");
                return;
        }

        ath_set_channel(sc);
}

#ifdef CONFIG_ATH9K_CHANNEL_CONTEXT

/*************/
/* Utilities */
/*************/

struct ath_chanctx* ath_is_go_chanctx_present(struct ath_softc *sc)
{
        struct ath_chanctx *ctx;
        struct ath_vif *avp;
        struct ieee80211_vif *vif;

        spin_lock_bh(&sc->chan_lock);

        ath_for_each_chanctx(sc, ctx) {
                if (!ctx->active)
                        continue;

                list_for_each_entry(avp, &ctx->vifs, list) {
                        vif = avp->vif;

                        if (ieee80211_vif_type_p2p(vif) == NL80211_IFTYPE_P2P_GO) {
                                spin_unlock_bh(&sc->chan_lock);
                                return ctx;
                        }
                }
        }

        spin_unlock_bh(&sc->chan_lock);
        return NULL;
}

/**********************************************************/
/* Functions to handle the channel context state machine. */
/**********************************************************/

static const char *offchannel_state_string(enum ath_offchannel_state state)
{
        switch (state) {
                case_rtn_string(ATH_OFFCHANNEL_IDLE);
                case_rtn_string(ATH_OFFCHANNEL_PROBE_SEND);
                case_rtn_string(ATH_OFFCHANNEL_PROBE_WAIT);
                case_rtn_string(ATH_OFFCHANNEL_SUSPEND);
                case_rtn_string(ATH_OFFCHANNEL_ROC_START);
                case_rtn_string(ATH_OFFCHANNEL_ROC_WAIT);
                case_rtn_string(ATH_OFFCHANNEL_ROC_DONE);
        default:
                return "unknown";
        }
}

static const char *chanctx_event_string(enum ath_chanctx_event ev)
{
        switch (ev) {
                case_rtn_string(ATH_CHANCTX_EVENT_BEACON_PREPARE);
                case_rtn_string(ATH_CHANCTX_EVENT_BEACON_SENT);
                case_rtn_string(ATH_CHANCTX_EVENT_TSF_TIMER);
                case_rtn_string(ATH_CHANCTX_EVENT_BEACON_RECEIVED);
                case_rtn_string(ATH_CHANCTX_EVENT_AUTHORIZED);
                case_rtn_string(ATH_CHANCTX_EVENT_SWITCH);
                case_rtn_string(ATH_CHANCTX_EVENT_ASSIGN);
                case_rtn_string(ATH_CHANCTX_EVENT_UNASSIGN);
                case_rtn_string(ATH_CHANCTX_EVENT_CHANGE);
                case_rtn_string(ATH_CHANCTX_EVENT_ENABLE_MULTICHANNEL);
        default:
                return "unknown";
        }
}

static const char *chanctx_state_string(enum ath_chanctx_state state)
{
        switch (state) {
                case_rtn_string(ATH_CHANCTX_STATE_IDLE);
                case_rtn_string(ATH_CHANCTX_STATE_WAIT_FOR_BEACON);
                case_rtn_string(ATH_CHANCTX_STATE_WAIT_FOR_TIMER);
                case_rtn_string(ATH_CHANCTX_STATE_SWITCH);
                case_rtn_string(ATH_CHANCTX_STATE_FORCE_ACTIVE);
        default:
                return "unknown";
        }
}

static u32 chanctx_event_delta(struct ath_softc *sc)
{
        u64 ms;
        struct timespec ts, *old;

        getrawmonotonic(&ts);
        old = &sc->last_event_time;
        ms = ts.tv_sec * 1000 + ts.tv_nsec / 1000000;
        ms -= old->tv_sec * 1000 + old->tv_nsec / 1000000;
        sc->last_event_time = ts;

        return (u32)ms;
}

void ath_chanctx_check_active(struct ath_softc *sc, struct ath_chanctx *ctx)
{
        struct ath_common *common = ath9k_hw_common(sc->sc_ah);
        struct ath_chanctx *ictx;
        struct ath_vif *avp;
        bool active = false;
        u8 n_active = 0;

        if (!ctx)
                return;

        if (ctx == &sc->offchannel.chan) {
                spin_lock_bh(&sc->chan_lock);

                if (likely(sc->sched.channel_switch_time))
                        ctx->flush_timeout =
                                usecs_to_jiffies(sc->sched.channel_switch_time);
                else
                        ctx->flush_timeout =
                                msecs_to_jiffies(10);

                spin_unlock_bh(&sc->chan_lock);

                /*
                 * There is no need to iterate over the
                 * active/assigned channel contexts if
                 * the current context is offchannel.
                 */
                return;
        }

        ictx = ctx;

        list_for_each_entry(avp, &ctx->vifs, list) {
                struct ieee80211_vif *vif = avp->vif;

                switch (vif->type) {
                case NL80211_IFTYPE_P2P_CLIENT:
                case NL80211_IFTYPE_STATION:
                        if (avp->assoc)
                                active = true;
                        break;
                default:
                        active = true;
                        break;
                }
        }
        ctx->active = active;

        ath_for_each_chanctx(sc, ctx) {
                if (!ctx->assigned || list_empty(&ctx->vifs))
                        continue;
                n_active++;
        }

        spin_lock_bh(&sc->chan_lock);

        if (n_active <= 1) {
                ictx->flush_timeout = HZ / 5;
                clear_bit(ATH_OP_MULTI_CHANNEL, &common->op_flags);
                spin_unlock_bh(&sc->chan_lock);
                return;
        }

        ictx->flush_timeout = usecs_to_jiffies(sc->sched.channel_switch_time);

        if (test_and_set_bit(ATH_OP_MULTI_CHANNEL, &common->op_flags)) {
                spin_unlock_bh(&sc->chan_lock);
                return;
        }

        spin_unlock_bh(&sc->chan_lock);

        if (ath9k_is_chanctx_enabled()) {
                ath_chanctx_event(sc, NULL,
                                  ATH_CHANCTX_EVENT_ENABLE_MULTICHANNEL);
        }
}

static struct ath_chanctx *
ath_chanctx_get_next(struct ath_softc *sc, struct ath_chanctx *ctx)
{
        int idx = ctx - &sc->chanctx[0];

        return &sc->chanctx[!idx];
}

static void ath_chanctx_adjust_tbtt_delta(struct ath_softc *sc)
{
        struct ath_chanctx *prev, *cur;
        struct timespec ts;
        u32 cur_tsf, prev_tsf, beacon_int;
        s32 offset;

        beacon_int = TU_TO_USEC(sc->cur_chan->beacon.beacon_interval);

        cur = sc->cur_chan;
        prev = ath_chanctx_get_next(sc, cur);

        if (!prev->switch_after_beacon)
                return;

        getrawmonotonic(&ts);
        cur_tsf = (u32) cur->tsf_val +
                  ath9k_hw_get_tsf_offset(&cur->tsf_ts, &ts);

        prev_tsf = prev->last_beacon - (u32) prev->tsf_val + cur_tsf;
        prev_tsf -= ath9k_hw_get_tsf_offset(&prev->tsf_ts, &ts);

        /* Adjust the TSF time of the AP chanctx to keep its beacons
         * at half beacon interval offset relative to the STA chanctx.
         */
        offset = cur_tsf - prev_tsf;

        /* Ignore stale data or spurious timestamps */
        if (offset < 0 || offset > 3 * beacon_int)
                return;

        offset = beacon_int / 2 - (offset % beacon_int);
        prev->tsf_val += offset;
}

/* Configure the TSF based hardware timer for a channel switch.
 * Also set up backup software timer, in case the gen timer fails.
 * This could be caused by a hardware reset.
 */
static void ath_chanctx_setup_timer(struct ath_softc *sc, u32 tsf_time)
{
        struct ath_common *common = ath9k_hw_common(sc->sc_ah);
        struct ath_hw *ah = sc->sc_ah;
        unsigned long timeout;

        ath9k_hw_gen_timer_start(ah, sc->p2p_ps_timer, tsf_time, 1000000);
        tsf_time -= ath9k_hw_gettsf32(ah);
        timeout = msecs_to_jiffies(tsf_time / 1000) + 1;
        mod_timer(&sc->sched.timer, jiffies + timeout);

        ath_dbg(common, CHAN_CTX,
                "Setup chanctx timer with timeout: %d (%d) ms\n",
                tsf_time / 1000, jiffies_to_msecs(timeout));
}

static void ath_chanctx_handle_bmiss(struct ath_softc *sc,
                                     struct ath_chanctx *ctx,
                                     struct ath_vif *avp)
{
        /*
         * Clear the extend_absence flag if it had been
         * set during the previous beacon transmission,
         * since we need to revert to the normal NoA
         * schedule.
         */
        if (ctx->active && sc->sched.extend_absence) {
                avp->noa_duration = 0;
                sc->sched.extend_absence = false;
        }

        /* If at least two consecutive beacons were missed on the STA
         * chanctx, stay on the STA channel for one extra beacon period,
         * to resync the timer properly.
         */
        if (ctx->active && sc->sched.beacon_miss >= 2) {
                avp->noa_duration = 0;
                sc->sched.extend_absence = true;
        }
}

static void ath_chanctx_offchannel_noa(struct ath_softc *sc,
                                       struct ath_chanctx *ctx,
                                       struct ath_vif *avp,
                                       u32 tsf_time)
{
        struct ath_common *common = ath9k_hw_common(sc->sc_ah);

        avp->noa_index++;
        avp->offchannel_start = tsf_time;
        avp->offchannel_duration = sc->sched.offchannel_duration;

        ath_dbg(common, CHAN_CTX,
                "offchannel noa_duration: %d, noa_start: %u, noa_index: %d\n",
                avp->offchannel_duration,
                avp->offchannel_start,
                avp->noa_index);

        /*
         * When multiple contexts are active, the NoA
         * has to be recalculated and advertised after
         * an offchannel operation.
         */
        if (ctx->active && avp->noa_duration)
                avp->noa_duration = 0;
}

static void ath_chanctx_set_periodic_noa(struct ath_softc *sc,
                                         struct ath_vif *avp,
                                         struct ath_beacon_config *cur_conf,
                                         u32 tsf_time,
                                         u32 beacon_int)
{
        struct ath_common *common = ath9k_hw_common(sc->sc_ah);

        avp->noa_index++;
        avp->noa_start = tsf_time;

        if (sc->sched.extend_absence)
                avp->noa_duration = (3 * beacon_int / 2) +
                        sc->sched.channel_switch_time;
        else
                avp->noa_duration =
                        TU_TO_USEC(cur_conf->beacon_interval) / 2 +
                        sc->sched.channel_switch_time;

        if (test_bit(ATH_OP_SCANNING, &common->op_flags) ||
            sc->sched.extend_absence)
                avp->periodic_noa = false;
        else
                avp->periodic_noa = true;

        ath_dbg(common, CHAN_CTX,
                "noa_duration: %d, noa_start: %u, noa_index: %d, periodic: %d\n",
                avp->noa_duration,
                avp->noa_start,
                avp->noa_index,
                avp->periodic_noa);
}

static void ath_chanctx_set_oneshot_noa(struct ath_softc *sc,
                                        struct ath_vif *avp,
                                        u32 tsf_time,
                                        u32 duration)
{
        struct ath_common *common = ath9k_hw_common(sc->sc_ah);

        avp->noa_index++;
        avp->noa_start = tsf_time;
        avp->periodic_noa = false;
        avp->oneshot_noa = true;
        avp->noa_duration = duration + sc->sched.channel_switch_time;

        ath_dbg(common, CHAN_CTX,
                "oneshot noa_duration: %d, noa_start: %u, noa_index: %d, periodic: %d\n",
                avp->noa_duration,
                avp->noa_start,
                avp->noa_index,
                avp->periodic_noa);
}

void ath_chanctx_event(struct ath_softc *sc, struct ieee80211_vif *vif,
                       enum ath_chanctx_event ev)
{
        struct ath_hw *ah = sc->sc_ah;
        struct ath_common *common = ath9k_hw_common(ah);
        struct ath_beacon_config *cur_conf;
        struct ath_vif *avp = NULL;
        struct ath_chanctx *ctx;
        u32 tsf_time;
        u32 beacon_int;

        if (vif)
                avp = (struct ath_vif *) vif->drv_priv;

        spin_lock_bh(&sc->chan_lock);

        ath_dbg(common, CHAN_CTX, "cur_chan: %d MHz, event: %s, state: %s, delta: %u ms\n",
                sc->cur_chan->chandef.center_freq1,
                chanctx_event_string(ev),
                chanctx_state_string(sc->sched.state),
                chanctx_event_delta(sc));

        switch (ev) {
        case ATH_CHANCTX_EVENT_BEACON_PREPARE:
                if (avp->offchannel_duration)
                        avp->offchannel_duration = 0;

                if (avp->oneshot_noa) {
                        avp->noa_duration = 0;
                        avp->oneshot_noa = false;

                        ath_dbg(common, CHAN_CTX,
                                "Clearing oneshot NoA\n");
                }

                if (avp->chanctx != sc->cur_chan) {
                        ath_dbg(common, CHAN_CTX,
                                "Contexts differ, not preparing beacon\n");
                        break;
                }

                if (sc->sched.offchannel_pending && !sc->sched.wait_switch) {
                        sc->sched.offchannel_pending = false;
                        sc->next_chan = &sc->offchannel.chan;
                        sc->sched.state = ATH_CHANCTX_STATE_WAIT_FOR_BEACON;
                        ath_dbg(common, CHAN_CTX,
                                "Setting offchannel_pending to false\n");
                }

                ctx = ath_chanctx_get_next(sc, sc->cur_chan);
                if (ctx->active && sc->sched.state == ATH_CHANCTX_STATE_IDLE) {
                        sc->next_chan = ctx;
                        sc->sched.state = ATH_CHANCTX_STATE_WAIT_FOR_BEACON;
                        ath_dbg(common, CHAN_CTX,
                                "Set next context, move chanctx state to WAIT_FOR_BEACON\n");
                }

                /* if the timer missed its window, use the next interval */
                if (sc->sched.state == ATH_CHANCTX_STATE_WAIT_FOR_TIMER) {
                        sc->sched.state = ATH_CHANCTX_STATE_WAIT_FOR_BEACON;
                        ath_dbg(common, CHAN_CTX,
                                "Move chanctx state from WAIT_FOR_TIMER to WAIT_FOR_BEACON\n");
                }

                if (sc->sched.mgd_prepare_tx)
                        sc->sched.state = ATH_CHANCTX_STATE_WAIT_FOR_BEACON;

                /*
                 * When a context becomes inactive, for example,
                 * disassociation of a station context, the NoA
                 * attribute needs to be removed from subsequent
                 * beacons.
                 */
                if (!ctx->active && avp->noa_duration &&
                    sc->sched.state != ATH_CHANCTX_STATE_WAIT_FOR_BEACON) {
                        avp->noa_duration = 0;
                        avp->periodic_noa = false;

                        ath_dbg(common, CHAN_CTX,
                                "Clearing NoA schedule\n");
                }

                if (sc->sched.state != ATH_CHANCTX_STATE_WAIT_FOR_BEACON)
                        break;

                ath_dbg(common, CHAN_CTX, "Preparing beacon for vif: %pM\n", vif->addr);

                sc->sched.beacon_pending = true;
                sc->sched.next_tbtt = REG_READ(ah, AR_NEXT_TBTT_TIMER);

                cur_conf = &sc->cur_chan->beacon;
                beacon_int = TU_TO_USEC(cur_conf->beacon_interval);

                /* defer channel switch by a quarter beacon interval */
                tsf_time = sc->sched.next_tbtt + beacon_int / 4;
                sc->sched.switch_start_time = tsf_time;
                sc->cur_chan->last_beacon = sc->sched.next_tbtt;

                /*
                 * If an offchannel switch is scheduled to happen after
                 * a beacon transmission, update the NoA with one-shot
                 * values and increment the index.
                 */
                if (sc->next_chan == &sc->offchannel.chan) {
                        ath_chanctx_offchannel_noa(sc, ctx, avp, tsf_time);
                        break;
                }

                ath_chanctx_handle_bmiss(sc, ctx, avp);

                /*
                 * If a mgd_prepare_tx() has been called by mac80211,
                 * a one-shot NoA needs to be sent. This can happen
                 * with one or more active channel contexts - in both
                 * cases, a new NoA schedule has to be advertised.
                 */
                if (sc->sched.mgd_prepare_tx) {
                        ath_chanctx_set_oneshot_noa(sc, avp, tsf_time,
                                                    jiffies_to_usecs(HZ / 5));
                        break;
                }

                /* Prevent wrap-around issues */
                if (avp->noa_duration && tsf_time - avp->noa_start > BIT(30))
                        avp->noa_duration = 0;

                /*
                 * If multiple contexts are active, start periodic
                 * NoA and increment the index for the first
                 * announcement.
                 */
                if (ctx->active &&
                    (!avp->noa_duration || sc->sched.force_noa_update))
                        ath_chanctx_set_periodic_noa(sc, avp, cur_conf,
                                                     tsf_time, beacon_int);

                if (ctx->active && sc->sched.force_noa_update)
                        sc->sched.force_noa_update = false;

                break;
        case ATH_CHANCTX_EVENT_BEACON_SENT:
                if (!sc->sched.beacon_pending) {
                        ath_dbg(common, CHAN_CTX,
                                "No pending beacon\n");
                        break;
                }

                sc->sched.beacon_pending = false;

                if (sc->sched.mgd_prepare_tx) {
                        sc->sched.mgd_prepare_tx = false;
                        complete(&sc->go_beacon);
                        ath_dbg(common, CHAN_CTX,
                                "Beacon sent, complete go_beacon\n");
                        break;
                }

                if (sc->sched.state != ATH_CHANCTX_STATE_WAIT_FOR_BEACON)
                        break;

                ath_dbg(common, CHAN_CTX,
                        "Move chanctx state to WAIT_FOR_TIMER\n");

                sc->sched.state = ATH_CHANCTX_STATE_WAIT_FOR_TIMER;
                ath_chanctx_setup_timer(sc, sc->sched.switch_start_time);
                break;
        case ATH_CHANCTX_EVENT_TSF_TIMER:
                if (sc->sched.state != ATH_CHANCTX_STATE_WAIT_FOR_TIMER)
                        break;

                if (!sc->cur_chan->switch_after_beacon &&
                    sc->sched.beacon_pending)
                        sc->sched.beacon_miss++;

                ath_dbg(common, CHAN_CTX,
                        "Move chanctx state to SWITCH\n");

                sc->sched.state = ATH_CHANCTX_STATE_SWITCH;
                ieee80211_queue_work(sc->hw, &sc->chanctx_work);
                break;
        case ATH_CHANCTX_EVENT_BEACON_RECEIVED:
                if (!test_bit(ATH_OP_MULTI_CHANNEL, &common->op_flags) ||
                    sc->cur_chan == &sc->offchannel.chan)
                        break;

                sc->sched.beacon_pending = false;
                sc->sched.beacon_miss = 0;

                if (sc->sched.state == ATH_CHANCTX_STATE_FORCE_ACTIVE ||
                    !sc->sched.beacon_adjust ||
                    !sc->cur_chan->tsf_val)
                        break;

                ath_chanctx_adjust_tbtt_delta(sc);

                /* TSF time might have been updated by the incoming beacon,
                 * need update the channel switch timer to reflect the change.
                 */
                tsf_time = sc->sched.switch_start_time;
                tsf_time -= (u32) sc->cur_chan->tsf_val +
                        ath9k_hw_get_tsf_offset(&sc->cur_chan->tsf_ts, NULL);
                tsf_time += ath9k_hw_gettsf32(ah);

                sc->sched.beacon_adjust = false;
                ath_chanctx_setup_timer(sc, tsf_time);
                break;
        case ATH_CHANCTX_EVENT_AUTHORIZED:
                if (sc->sched.state != ATH_CHANCTX_STATE_FORCE_ACTIVE ||
                    avp->chanctx != sc->cur_chan)
                        break;

                ath_dbg(common, CHAN_CTX,
                        "Move chanctx state from FORCE_ACTIVE to IDLE\n");

                sc->sched.state = ATH_CHANCTX_STATE_IDLE;
                /* fall through */
        case ATH_CHANCTX_EVENT_SWITCH:
                if (!test_bit(ATH_OP_MULTI_CHANNEL, &common->op_flags) ||
                    sc->sched.state == ATH_CHANCTX_STATE_FORCE_ACTIVE ||
                    sc->cur_chan->switch_after_beacon ||
                    sc->cur_chan == &sc->offchannel.chan)
                        break;

                /* If this is a station chanctx, stay active for a half
                 * beacon period (minus channel switch time)
                 */
                sc->next_chan = ath_chanctx_get_next(sc, sc->cur_chan);
                cur_conf = &sc->cur_chan->beacon;

                ath_dbg(common, CHAN_CTX,
                        "Move chanctx state to WAIT_FOR_TIMER (event SWITCH)\n");

                sc->sched.state = ATH_CHANCTX_STATE_WAIT_FOR_TIMER;
                sc->sched.wait_switch = false;

                tsf_time = TU_TO_USEC(cur_conf->beacon_interval) / 2;

                if (sc->sched.extend_absence) {
                        sc->sched.beacon_miss = 0;
                        tsf_time *= 3;
                }

                tsf_time -= sc->sched.channel_switch_time;
                tsf_time += ath9k_hw_gettsf32(sc->sc_ah);
                sc->sched.switch_start_time = tsf_time;

                ath_chanctx_setup_timer(sc, tsf_time);
                sc->sched.beacon_pending = true;
                sc->sched.beacon_adjust = true;
                break;
        case ATH_CHANCTX_EVENT_ENABLE_MULTICHANNEL:
                if (sc->cur_chan == &sc->offchannel.chan ||
                    sc->cur_chan->switch_after_beacon)
                        break;

                sc->next_chan = ath_chanctx_get_next(sc, sc->cur_chan);
                ieee80211_queue_work(sc->hw, &sc->chanctx_work);
                break;
        case ATH_CHANCTX_EVENT_UNASSIGN:
                if (sc->cur_chan->assigned) {
                        if (sc->next_chan && !sc->next_chan->assigned &&
                            sc->next_chan != &sc->offchannel.chan)
                                sc->sched.state = ATH_CHANCTX_STATE_IDLE;
                        break;
                }

                ctx = ath_chanctx_get_next(sc, sc->cur_chan);
                sc->sched.state = ATH_CHANCTX_STATE_IDLE;
                if (!ctx->assigned)
                        break;

                sc->next_chan = ctx;
                ieee80211_queue_work(sc->hw, &sc->chanctx_work);
                break;
        case ATH_CHANCTX_EVENT_ASSIGN:
                break;
        case ATH_CHANCTX_EVENT_CHANGE:
                break;
        }

        spin_unlock_bh(&sc->chan_lock);
}

void ath_chanctx_beacon_sent_ev(struct ath_softc *sc,
                                enum ath_chanctx_event ev)
{
        if (sc->sched.beacon_pending)
                ath_chanctx_event(sc, NULL, ev);
}

void ath_chanctx_beacon_recv_ev(struct ath_softc *sc,
                                enum ath_chanctx_event ev)
{
        ath_chanctx_event(sc, NULL, ev);
}

static int ath_scan_channel_duration(struct ath_softc *sc,
                                     struct ieee80211_channel *chan)
{
        struct cfg80211_scan_request *req = sc->offchannel.scan_req;

        if (!req->n_ssids || (chan->flags & IEEE80211_CHAN_NO_IR))
                return (HZ / 9); /* ~110 ms */

        return (HZ / 16); /* ~60 ms */
}

static void ath_chanctx_switch(struct ath_softc *sc, struct ath_chanctx *ctx,
                               struct cfg80211_chan_def *chandef)
{
        struct ath_common *common = ath9k_hw_common(sc->sc_ah);

        spin_lock_bh(&sc->chan_lock);

        if (test_bit(ATH_OP_MULTI_CHANNEL, &common->op_flags) &&
            (sc->cur_chan != ctx) && (ctx == &sc->offchannel.chan)) {
                if (chandef)
                        ctx->chandef = *chandef;

                sc->sched.offchannel_pending = true;
                sc->sched.wait_switch = true;
                sc->sched.offchannel_duration =
                        jiffies_to_usecs(sc->offchannel.duration) +
                        sc->sched.channel_switch_time;

                spin_unlock_bh(&sc->chan_lock);
                ath_dbg(common, CHAN_CTX,
                        "Set offchannel_pending to true\n");
                return;
        }

        sc->next_chan = ctx;
        if (chandef) {
                ctx->chandef = *chandef;
                ath_dbg(common, CHAN_CTX,
                        "Assigned next_chan to %d MHz\n", chandef->center_freq1);
        }

        if (sc->next_chan == &sc->offchannel.chan) {
                sc->sched.offchannel_duration =
                        jiffies_to_usecs(sc->offchannel.duration) +
                        sc->sched.channel_switch_time;

                if (chandef) {
                        ath_dbg(common, CHAN_CTX,
                                "Offchannel duration for chan %d MHz : %u\n",
                                chandef->center_freq1,
                                sc->sched.offchannel_duration);
                }
        }
        spin_unlock_bh(&sc->chan_lock);
        ieee80211_queue_work(sc->hw, &sc->chanctx_work);
}

static void ath_chanctx_offchan_switch(struct ath_softc *sc,
                                       struct ieee80211_channel *chan)
{
        struct ath_common *common = ath9k_hw_common(sc->sc_ah);
        struct cfg80211_chan_def chandef;

        cfg80211_chandef_create(&chandef, chan, NL80211_CHAN_NO_HT);
        ath_dbg(common, CHAN_CTX,
                "Channel definition created: %d MHz\n", chandef.center_freq1);

        ath_chanctx_switch(sc, &sc->offchannel.chan, &chandef);
}

static struct ath_chanctx *ath_chanctx_get_oper_chan(struct ath_softc *sc,
                                                     bool active)
{
        struct ath_chanctx *ctx;

        ath_for_each_chanctx(sc, ctx) {
                if (!ctx->assigned || list_empty(&ctx->vifs))
                        continue;
                if (active && !ctx->active)
                        continue;

                if (ctx->switch_after_beacon)
                        return ctx;
        }

        return &sc->chanctx[0];
}

static void
ath_scan_next_channel(struct ath_softc *sc)
{
        struct ath_common *common = ath9k_hw_common(sc->sc_ah);
        struct cfg80211_scan_request *req = sc->offchannel.scan_req;
        struct ieee80211_channel *chan;

        if (sc->offchannel.scan_idx >= req->n_channels) {
                ath_dbg(common, CHAN_CTX,
                        "Moving offchannel state to ATH_OFFCHANNEL_IDLE, "
                        "scan_idx: %d, n_channels: %d\n",
                        sc->offchannel.scan_idx,
                        req->n_channels);

                sc->offchannel.state = ATH_OFFCHANNEL_IDLE;
                ath_chanctx_switch(sc, ath_chanctx_get_oper_chan(sc, false),
                                   NULL);
                return;
        }

        ath_dbg(common, CHAN_CTX,
                "Moving offchannel state to ATH_OFFCHANNEL_PROBE_SEND, scan_idx: %d\n",
                sc->offchannel.scan_idx);

        chan = req->channels[sc->offchannel.scan_idx++];
        sc->offchannel.duration = ath_scan_channel_duration(sc, chan);
        sc->offchannel.state = ATH_OFFCHANNEL_PROBE_SEND;

        ath_chanctx_offchan_switch(sc, chan);
}

void ath_offchannel_next(struct ath_softc *sc)
{
        struct ieee80211_vif *vif;

        if (sc->offchannel.scan_req) {
                vif = sc->offchannel.scan_vif;
                sc->offchannel.chan.txpower = vif->bss_conf.txpower;
                ath_scan_next_channel(sc);
        } else if (sc->offchannel.roc_vif) {
                vif = sc->offchannel.roc_vif;
                sc->offchannel.chan.txpower = vif->bss_conf.txpower;
                sc->offchannel.duration =
                        msecs_to_jiffies(sc->offchannel.roc_duration);
                sc->offchannel.state = ATH_OFFCHANNEL_ROC_START;
                ath_chanctx_offchan_switch(sc, sc->offchannel.roc_chan);
        } else {
                spin_lock_bh(&sc->chan_lock);
                sc->sched.offchannel_pending = false;
                sc->sched.wait_switch = false;
                spin_unlock_bh(&sc->chan_lock);

                ath_chanctx_switch(sc, ath_chanctx_get_oper_chan(sc, false),
                                   NULL);
                sc->offchannel.state = ATH_OFFCHANNEL_IDLE;
                if (sc->ps_idle)
                        ath_cancel_work(sc);
        }
}

void ath_roc_complete(struct ath_softc *sc, enum ath_roc_complete_reason reason)
{
        struct ath_common *common = ath9k_hw_common(sc->sc_ah);

        sc->offchannel.roc_vif = NULL;
        sc->offchannel.roc_chan = NULL;

        switch (reason) {
        case ATH_ROC_COMPLETE_ABORT:
                ath_dbg(common, CHAN_CTX, "RoC aborted\n");
                ieee80211_remain_on_channel_expired(sc->hw);
                break;
        case ATH_ROC_COMPLETE_EXPIRE:
                ath_dbg(common, CHAN_CTX, "RoC expired\n");
                ieee80211_remain_on_channel_expired(sc->hw);
                break;
        case ATH_ROC_COMPLETE_CANCEL:
                ath_dbg(common, CHAN_CTX, "RoC canceled\n");
                break;
        }

        ath_offchannel_next(sc);
        ath9k_ps_restore(sc);
}

void ath_scan_complete(struct ath_softc *sc, bool abort)
{
        struct ath_common *common = ath9k_hw_common(sc->sc_ah);
        struct cfg80211_scan_info info = {
                .aborted = abort,
        };

        if (abort)
                ath_dbg(common, CHAN_CTX, "HW scan aborted\n");
        else
                ath_dbg(common, CHAN_CTX, "HW scan complete\n");

        sc->offchannel.scan_req = NULL;
        sc->offchannel.scan_vif = NULL;
        sc->offchannel.state = ATH_OFFCHANNEL_IDLE;
        ieee80211_scan_completed(sc->hw, &info);
        clear_bit(ATH_OP_SCANNING, &common->op_flags);
        spin_lock_bh(&sc->chan_lock);
        if (test_bit(ATH_OP_MULTI_CHANNEL, &common->op_flags))
                sc->sched.force_noa_update = true;
        spin_unlock_bh(&sc->chan_lock);
        ath_offchannel_next(sc);
        ath9k_ps_restore(sc);
}

static void ath_scan_send_probe(struct ath_softc *sc,
                                struct cfg80211_ssid *ssid)
{
        struct cfg80211_scan_request *req = sc->offchannel.scan_req;
        struct ieee80211_vif *vif = sc->offchannel.scan_vif;
        struct ath_tx_control txctl = {};
        struct sk_buff *skb;
        struct ieee80211_tx_info *info;
        int band = sc->offchannel.chan.chandef.chan->band;

        skb = ieee80211_probereq_get(sc->hw, vif->addr,
                        ssid->ssid, ssid->ssid_len, req->ie_len);
        if (!skb)

                return;

        info = IEEE80211_SKB_CB(skb);
        if (req->no_cck)
                info->flags |= IEEE80211_TX_CTL_NO_CCK_RATE;

        if (req->ie_len)
                memcpy(skb_put(skb, req->ie_len), req->ie, req->ie_len);

        skb_set_queue_mapping(skb, IEEE80211_AC_VO);

        if (!ieee80211_tx_prepare_skb(sc->hw, vif, skb, band, NULL))
                goto error;

        txctl.txq = sc->tx.txq_map[IEEE80211_AC_VO];
        if (ath_tx_start(sc->hw, skb, &txctl))
                goto error;

        return;

error:
        ieee80211_free_txskb(sc->hw, skb);
}

static void ath_scan_channel_start(struct ath_softc *sc)
{
        struct ath_common *common = ath9k_hw_common(sc->sc_ah);
        struct cfg80211_scan_request *req = sc->offchannel.scan_req;
        int i;

        if (!(sc->cur_chan->chandef.chan->flags & IEEE80211_CHAN_NO_IR) &&
            req->n_ssids) {
                for (i = 0; i < req->n_ssids; i++)
                        ath_scan_send_probe(sc, &req->ssids[i]);

        }

        ath_dbg(common, CHAN_CTX,
                "Moving offchannel state to ATH_OFFCHANNEL_PROBE_WAIT\n");

        sc->offchannel.state = ATH_OFFCHANNEL_PROBE_WAIT;
        mod_timer(&sc->offchannel.timer, jiffies + sc->offchannel.duration);
}

static void ath_chanctx_timer(unsigned long data)
{
        struct ath_softc *sc = (struct ath_softc *) data;
        struct ath_common *common = ath9k_hw_common(sc->sc_ah);

        ath_dbg(common, CHAN_CTX,
                "Channel context timer invoked\n");

        ath_chanctx_event(sc, NULL, ATH_CHANCTX_EVENT_TSF_TIMER);
}

static void ath_offchannel_timer(unsigned long data)
{
        struct ath_softc *sc = (struct ath_softc *)data;
        struct ath_chanctx *ctx;
        struct ath_common *common = ath9k_hw_common(sc->sc_ah);

        ath_dbg(common, CHAN_CTX, "%s: offchannel state: %s\n",
                __func__, offchannel_state_string(sc->offchannel.state));

        switch (sc->offchannel.state) {
        case ATH_OFFCHANNEL_PROBE_WAIT:
                if (!sc->offchannel.scan_req)
                        return;

                /* get first active channel context */
                ctx = ath_chanctx_get_oper_chan(sc, true);
                if (ctx->active) {
                        ath_dbg(common, CHAN_CTX,
                                "Switch to oper/active context, "
                                "move offchannel state to ATH_OFFCHANNEL_SUSPEND\n");

                        sc->offchannel.state = ATH_OFFCHANNEL_SUSPEND;
                        ath_chanctx_switch(sc, ctx, NULL);
                        mod_timer(&sc->offchannel.timer, jiffies + HZ / 10);
                        break;
                }
                /* fall through */
        case ATH_OFFCHANNEL_SUSPEND:
                if (!sc->offchannel.scan_req)
                        return;

                ath_scan_next_channel(sc);
                break;
        case ATH_OFFCHANNEL_ROC_START:
        case ATH_OFFCHANNEL_ROC_WAIT:
                sc->offchannel.state = ATH_OFFCHANNEL_ROC_DONE;
                ath_roc_complete(sc, ATH_ROC_COMPLETE_EXPIRE);
                break;
        default:
                break;
        }
}

static bool
ath_chanctx_send_vif_ps_frame(struct ath_softc *sc, struct ath_vif *avp,
                              bool powersave)
{
        struct ieee80211_vif *vif = avp->vif;
        struct ieee80211_sta *sta = NULL;
        struct ieee80211_hdr_3addr *nullfunc;
        struct ath_tx_control txctl;
        struct sk_buff *skb;
        int band = sc->cur_chan->chandef.chan->band;

        switch (vif->type) {
        case NL80211_IFTYPE_STATION:
                if (!avp->assoc)
                        return false;

                skb = ieee80211_nullfunc_get(sc->hw, vif);
                if (!skb)
                        return false;

                nullfunc = (struct ieee80211_hdr_3addr *) skb->data;
                if (powersave)
                        nullfunc->frame_control |=
                                cpu_to_le16(IEEE80211_FCTL_PM);

                skb->priority = 7;
                skb_set_queue_mapping(skb, IEEE80211_AC_VO);
                if (!ieee80211_tx_prepare_skb(sc->hw, vif, skb, band, &sta)) {
                        dev_kfree_skb_any(skb);
                        return false;
                }
                break;
        default:
                return false;
        }

        memset(&txctl, 0, sizeof(txctl));
        txctl.txq = sc->tx.txq_map[IEEE80211_AC_VO];
        txctl.sta = sta;
        if (ath_tx_start(sc->hw, skb, &txctl)) {
                ieee80211_free_txskb(sc->hw, skb);
                return false;
        }

        return true;
}

static bool
ath_chanctx_send_ps_frame(struct ath_softc *sc, bool powersave)
{
        struct ath_vif *avp;
        bool sent = false;

        rcu_read_lock();
        list_for_each_entry(avp, &sc->cur_chan->vifs, list) {
                if (ath_chanctx_send_vif_ps_frame(sc, avp, powersave))
                        sent = true;
        }
        rcu_read_unlock();

        return sent;
}

static bool ath_chanctx_defer_switch(struct ath_softc *sc)
{
        struct ath_common *common = ath9k_hw_common(sc->sc_ah);

        if (sc->cur_chan == &sc->offchannel.chan)
                return false;

        switch (sc->sched.state) {
        case ATH_CHANCTX_STATE_SWITCH:
                return false;
        case ATH_CHANCTX_STATE_IDLE:
                if (!sc->cur_chan->switch_after_beacon)
                        return false;

                ath_dbg(common, CHAN_CTX,
                        "Defer switch, set chanctx state to WAIT_FOR_BEACON\n");

                sc->sched.state = ATH_CHANCTX_STATE_WAIT_FOR_BEACON;
                break;
        default:
                break;
        }

        return true;
}

static void ath_offchannel_channel_change(struct ath_softc *sc)
{
        struct ath_common *common = ath9k_hw_common(sc->sc_ah);

        ath_dbg(common, CHAN_CTX, "%s: offchannel state: %s\n",
                __func__, offchannel_state_string(sc->offchannel.state));

        switch (sc->offchannel.state) {
        case ATH_OFFCHANNEL_PROBE_SEND:
                if (!sc->offchannel.scan_req)
                        return;

                if (sc->cur_chan->chandef.chan !=
                    sc->offchannel.chan.chandef.chan)
                        return;

                ath_scan_channel_start(sc);
                break;
        case ATH_OFFCHANNEL_IDLE:
                if (!sc->offchannel.scan_req)
                        return;

                ath_scan_complete(sc, false);
                break;
        case ATH_OFFCHANNEL_ROC_START:
                if (sc->cur_chan != &sc->offchannel.chan)
                        break;

                sc->offchannel.state = ATH_OFFCHANNEL_ROC_WAIT;
                mod_timer(&sc->offchannel.timer,
                          jiffies + sc->offchannel.duration);
                ieee80211_ready_on_channel(sc->hw);
                break;
        case ATH_OFFCHANNEL_ROC_DONE:
                break;
        default:
                break;
        }
}

void ath_chanctx_set_next(struct ath_softc *sc, bool force)
{
        struct ath_common *common = ath9k_hw_common(sc->sc_ah);
        struct ath_chanctx *old_ctx;
        struct timespec ts;
        bool measure_time = false;
        bool send_ps = false;
        bool queues_stopped = false;

        spin_lock_bh(&sc->chan_lock);
        if (!sc->next_chan) {
                spin_unlock_bh(&sc->chan_lock);
                return;
        }

        if (!force && ath_chanctx_defer_switch(sc)) {
                spin_unlock_bh(&sc->chan_lock);
                return;
        }

        ath_dbg(common, CHAN_CTX,
                "%s: current: %d MHz, next: %d MHz\n",
                __func__,
                sc->cur_chan->chandef.center_freq1,
                sc->next_chan->chandef.center_freq1);

        if (sc->cur_chan != sc->next_chan) {
                ath_dbg(common, CHAN_CTX,
                        "Stopping current chanctx: %d\n",
                        sc->cur_chan->chandef.center_freq1);
                sc->cur_chan->stopped = true;
                spin_unlock_bh(&sc->chan_lock);

                if (sc->next_chan == &sc->offchannel.chan) {
                        getrawmonotonic(&ts);
                        measure_time = true;
                }

                ath9k_chanctx_stop_queues(sc, sc->cur_chan);
                queues_stopped = true;

                __ath9k_flush(sc->hw, ~0, true, false, false);

                if (ath_chanctx_send_ps_frame(sc, true))
                        __ath9k_flush(sc->hw, BIT(IEEE80211_AC_VO),
                                      false, false, false);

                send_ps = true;
                spin_lock_bh(&sc->chan_lock);

                if (sc->cur_chan != &sc->offchannel.chan) {
                        getrawmonotonic(&sc->cur_chan->tsf_ts);
                        sc->cur_chan->tsf_val = ath9k_hw_gettsf64(sc->sc_ah);
                }
        }
        old_ctx = sc->cur_chan;
        sc->cur_chan = sc->next_chan;
        sc->cur_chan->stopped = false;
        sc->next_chan = NULL;

        if (!sc->sched.offchannel_pending)
                sc->sched.offchannel_duration = 0;

        if (sc->sched.state != ATH_CHANCTX_STATE_FORCE_ACTIVE)
                sc->sched.state = ATH_CHANCTX_STATE_IDLE;

        spin_unlock_bh(&sc->chan_lock);

        if (sc->sc_ah->chip_fullsleep ||
            memcmp(&sc->cur_chandef, &sc->cur_chan->chandef,
                   sizeof(sc->cur_chandef))) {
                ath_dbg(common, CHAN_CTX,
                        "%s: Set channel %d MHz\n",
                        __func__, sc->cur_chan->chandef.center_freq1);
                ath_set_channel(sc);
                if (measure_time)
                        sc->sched.channel_switch_time =
                                ath9k_hw_get_tsf_offset(&ts, NULL);
                /*
                 * A reset will ensure that all queues are woken up,
                 * so there is no need to awaken them again.
                 */
                goto out;
        }

        if (queues_stopped)
                ath9k_chanctx_wake_queues(sc, old_ctx);
out:
        if (send_ps)
                ath_chanctx_send_ps_frame(sc, false);

        ath_offchannel_channel_change(sc);
        ath_chanctx_event(sc, NULL, ATH_CHANCTX_EVENT_SWITCH);
}

static void ath_chanctx_work(struct work_struct *work)
{
        struct ath_softc *sc = container_of(work, struct ath_softc,
                                            chanctx_work);
        mutex_lock(&sc->mutex);
        ath_chanctx_set_next(sc, false);
        mutex_unlock(&sc->mutex);
}

void ath9k_offchannel_init(struct ath_softc *sc)
{
        struct ath_chanctx *ctx;
        struct ath_common *common = ath9k_hw_common(sc->sc_ah);
        struct ieee80211_supported_band *sband;
        struct ieee80211_channel *chan;
        int i;

        sband = &common->sbands[NL80211_BAND_2GHZ];
        if (!sband->n_channels)
                sband = &common->sbands[NL80211_BAND_5GHZ];

        chan = &sband->channels[0];

        ctx = &sc->offchannel.chan;
        INIT_LIST_HEAD(&ctx->vifs);
        ctx->txpower = ATH_TXPOWER_MAX;
        cfg80211_chandef_create(&ctx->chandef, chan, NL80211_CHAN_HT20);

        for (i = 0; i < ARRAY_SIZE(ctx->acq); i++) {
                INIT_LIST_HEAD(&ctx->acq[i].acq_new);
                INIT_LIST_HEAD(&ctx->acq[i].acq_old);
                spin_lock_init(&ctx->acq[i].lock);
        }

        sc->offchannel.chan.offchannel = true;
}

void ath9k_init_channel_context(struct ath_softc *sc)
{
        INIT_WORK(&sc->chanctx_work, ath_chanctx_work);

        setup_timer(&sc->offchannel.timer, ath_offchannel_timer,
                    (unsigned long)sc);
        setup_timer(&sc->sched.timer, ath_chanctx_timer,
                    (unsigned long)sc);

        init_completion(&sc->go_beacon);
}

void ath9k_deinit_channel_context(struct ath_softc *sc)
{
        cancel_work_sync(&sc->chanctx_work);
}

bool ath9k_is_chanctx_enabled(void)
{
        return (ath9k_use_chanctx == 1);
}

/********************/
/* Queue management */
/********************/

void ath9k_chanctx_stop_queues(struct ath_softc *sc, struct ath_chanctx *ctx)
{
        struct ath_hw *ah = sc->sc_ah;
        int i;

        if (ctx == &sc->offchannel.chan) {
                ieee80211_stop_queue(sc->hw,
                                     sc->hw->offchannel_tx_hw_queue);
        } else {
                for (i = 0; i < IEEE80211_NUM_ACS; i++)
                        ieee80211_stop_queue(sc->hw,
                                             ctx->hw_queue_base + i);
        }

        if (ah->opmode == NL80211_IFTYPE_AP)
                ieee80211_stop_queue(sc->hw, sc->hw->queues - 2);
}


void ath9k_chanctx_wake_queues(struct ath_softc *sc, struct ath_chanctx *ctx)
{
        struct ath_hw *ah = sc->sc_ah;
        int i;

        if (ctx == &sc->offchannel.chan) {
                ieee80211_wake_queue(sc->hw,
                                     sc->hw->offchannel_tx_hw_queue);
        } else {
                for (i = 0; i < IEEE80211_NUM_ACS; i++)
                        ieee80211_wake_queue(sc->hw,
                                             ctx->hw_queue_base + i);
        }

        if (ah->opmode == NL80211_IFTYPE_AP)
                ieee80211_wake_queue(sc->hw, sc->hw->queues - 2);
}

/*****************/
/* P2P Powersave */
/*****************/

static void ath9k_update_p2p_ps_timer(struct ath_softc *sc, struct ath_vif *avp)
{
        struct ath_common *common = ath9k_hw_common(sc->sc_ah);
        struct ath_hw *ah = sc->sc_ah;
        u32 tsf, target_tsf;

        if (!avp || !avp->noa.has_next_tsf)
                return;

        ath9k_hw_gen_timer_stop(ah, sc->p2p_ps_timer);

        tsf = ath9k_hw_gettsf32(sc->sc_ah);

        target_tsf = avp->noa.next_tsf;
        if (!avp->noa.absent)
                target_tsf -= ATH_P2P_PS_STOP_TIME;
        else
                target_tsf += ATH_P2P_PS_STOP_TIME;

        if (target_tsf - tsf < ATH_P2P_PS_STOP_TIME)
                target_tsf = tsf + ATH_P2P_PS_STOP_TIME;

        ath_dbg(common, CHAN_CTX, "%s absent %d tsf 0x%08X next_tsf 0x%08X (%dms)\n",
                __func__, avp->noa.absent, tsf, target_tsf,
                (target_tsf - tsf) / 1000);

        ath9k_hw_gen_timer_start(ah, sc->p2p_ps_timer, target_tsf, 1000000);
}

static void ath9k_update_p2p_ps(struct ath_softc *sc, struct ieee80211_vif *vif)
{
        struct ath_vif *avp = (void *)vif->drv_priv;
        u32 tsf;

        if (!sc->p2p_ps_timer)
                return;

        if (vif->type != NL80211_IFTYPE_STATION)
                return;

        sc->p2p_ps_vif = avp;

        if (sc->ps_flags & PS_BEACON_SYNC)
                return;

        tsf = ath9k_hw_gettsf32(sc->sc_ah);
        ieee80211_parse_p2p_noa(&vif->bss_conf.p2p_noa_attr, &avp->noa, tsf);
        ath9k_update_p2p_ps_timer(sc, avp);
}

static u8 ath9k_get_ctwin(struct ath_softc *sc, struct ath_vif *avp)
{
        struct ath_beacon_config *cur_conf = &sc->cur_chan->beacon;
        u8 switch_time, ctwin;

        /*
         * Channel switch in multi-channel mode is deferred
         * by a quarter beacon interval when handling
         * ATH_CHANCTX_EVENT_BEACON_PREPARE, so the P2P-GO
         * interface is guaranteed to be discoverable
         * for that duration after a TBTT.
         */
        switch_time = cur_conf->beacon_interval / 4;

        ctwin = avp->vif->bss_conf.p2p_noa_attr.oppps_ctwindow;
        if (ctwin && (ctwin < switch_time))
                return ctwin;

        if (switch_time < P2P_DEFAULT_CTWIN)
                return 0;

        return P2P_DEFAULT_CTWIN;
}

void ath9k_beacon_add_noa(struct ath_softc *sc, struct ath_vif *avp,
                          struct sk_buff *skb)
{
        static const u8 noa_ie_hdr[] = {
                WLAN_EID_VENDOR_SPECIFIC,       /* type */
                0,                              /* length */
                0x50, 0x6f, 0x9a,               /* WFA OUI */
                0x09,                           /* P2P subtype */
                0x0c,                           /* Notice of Absence */
                0x00,                           /* LSB of little-endian len */
                0x00,                           /* MSB of little-endian len */
        };

        struct ieee80211_p2p_noa_attr *noa;
        int noa_len, noa_desc, i = 0;
        u8 *hdr;

        if (!avp->offchannel_duration && !avp->noa_duration)
                return;

        noa_desc = !!avp->offchannel_duration + !!avp->noa_duration;
        noa_len = 2 + sizeof(struct ieee80211_p2p_noa_desc) * noa_desc;

        hdr = skb_put(skb, sizeof(noa_ie_hdr));
        memcpy(hdr, noa_ie_hdr, sizeof(noa_ie_hdr));
        hdr[1] = sizeof(noa_ie_hdr) + noa_len - 2;
        hdr[7] = noa_len;

        noa = (void *) skb_put(skb, noa_len);
        memset(noa, 0, noa_len);

        noa->index = avp->noa_index;
        noa->oppps_ctwindow = ath9k_get_ctwin(sc, avp);
        if (noa->oppps_ctwindow)
                noa->oppps_ctwindow |= BIT(7);

        if (avp->noa_duration) {
                if (avp->periodic_noa) {
                        u32 interval = TU_TO_USEC(sc->cur_chan->beacon.beacon_interval);
                        noa->desc[i].count = 255;
                        noa->desc[i].interval = cpu_to_le32(interval);
                } else {
                        noa->desc[i].count = 1;
                }

                noa->desc[i].start_time = cpu_to_le32(avp->noa_start);
                noa->desc[i].duration = cpu_to_le32(avp->noa_duration);
                i++;
        }

        if (avp->offchannel_duration) {
                noa->desc[i].count = 1;
                noa->desc[i].start_time = cpu_to_le32(avp->offchannel_start);
                noa->desc[i].duration = cpu_to_le32(avp->offchannel_duration);
        }
}

void ath9k_p2p_ps_timer(void *priv)
{
        struct ath_softc *sc = priv;
        struct ath_vif *avp = sc->p2p_ps_vif;
        struct ieee80211_vif *vif;
        struct ieee80211_sta *sta;
        struct ath_node *an;
        u32 tsf;

        del_timer_sync(&sc->sched.timer);
        ath9k_hw_gen_timer_stop(sc->sc_ah, sc->p2p_ps_timer);
        ath_chanctx_event(sc, NULL, ATH_CHANCTX_EVENT_TSF_TIMER);

        if (!avp || avp->chanctx != sc->cur_chan)
                return;

        tsf = ath9k_hw_gettsf32(sc->sc_ah);
        if (!avp->noa.absent)
                tsf += ATH_P2P_PS_STOP_TIME;
        else
                tsf -= ATH_P2P_PS_STOP_TIME;

        if (!avp->noa.has_next_tsf ||
            avp->noa.next_tsf - tsf > BIT(31))
                ieee80211_update_p2p_noa(&avp->noa, tsf);

        ath9k_update_p2p_ps_timer(sc, avp);

        rcu_read_lock();

        vif = avp->vif;
        sta = ieee80211_find_sta(vif, avp->bssid);
        if (!sta)
                goto out;

        an = (void *) sta->drv_priv;
        if (an->sleeping == !!avp->noa.absent)
                goto out;

        an->sleeping = avp->noa.absent;
        if (an->sleeping)
                ath_tx_aggr_sleep(sta, sc, an);
        else
                ath_tx_aggr_wakeup(sc, an);

out:
        rcu_read_unlock();
}

void ath9k_p2p_bss_info_changed(struct ath_softc *sc,
                                struct ieee80211_vif *vif)
{
        unsigned long flags;

        spin_lock_bh(&sc->sc_pcu_lock);
        spin_lock_irqsave(&sc->sc_pm_lock, flags);
        ath9k_update_p2p_ps(sc, vif);
        spin_unlock_irqrestore(&sc->sc_pm_lock, flags);
        spin_unlock_bh(&sc->sc_pcu_lock);
}

void ath9k_p2p_beacon_sync(struct ath_softc *sc)
{
        if (sc->p2p_ps_vif)
                ath9k_update_p2p_ps(sc, sc->p2p_ps_vif->vif);
}

void ath9k_p2p_remove_vif(struct ath_softc *sc,
                          struct ieee80211_vif *vif)
{
        struct ath_vif *avp = (void *)vif->drv_priv;

        spin_lock_bh(&sc->sc_pcu_lock);
        if (avp == sc->p2p_ps_vif) {
                sc->p2p_ps_vif = NULL;
                ath9k_update_p2p_ps_timer(sc, NULL);
        }
        spin_unlock_bh(&sc->sc_pcu_lock);
}

int ath9k_init_p2p(struct ath_softc *sc)
{
        sc->p2p_ps_timer = ath_gen_timer_alloc(sc->sc_ah, ath9k_p2p_ps_timer,
                                               NULL, sc, AR_FIRST_NDP_TIMER);
        if (!sc->p2p_ps_timer)
                return -ENOMEM;

        return 0;
}

void ath9k_deinit_p2p(struct ath_softc *sc)
{
        if (sc->p2p_ps_timer)
                ath_gen_timer_free(sc->sc_ah, sc->p2p_ps_timer);
}

#endif /* CONFIG_ATH9K_CHANNEL_CONTEXT */