ath9k: Implement remain-on-channal support

Add remain on channel support in order to enable multi-channel
concurrency.

Signed-off-by: Felix Fietkau <[e-mail]>
Signed-off-by: Rajkumar Manoharan <[e-mail]>
Signed-off-by: John W. Linville <[e-mail]>

drivers/net/wireless/ath/ath9k/ath9k.h

···
 	ATH_OFFCHANNEL_PROBE_SEND,
 	ATH_OFFCHANNEL_PROBE_WAIT,
 	ATH_OFFCHANNEL_SUSPEND,
+	ATH_OFFCHANNEL_ROC_START,
+	ATH_OFFCHANNEL_ROC_WAIT,
+	ATH_OFFCHANNEL_ROC_DONE,
 };
 
 struct ath_offchannel {
···
 	struct ieee80211_vif *scan_vif;
 	int scan_idx;
 	enum ath_offchannel_state state;
+	struct ieee80211_channel *roc_chan;
+	struct ieee80211_vif *roc_vif;
+	int roc_duration;
 };
 
 void ath9k_fill_chanctx_ops(void);

drivers/net/wireless/ath/ath9k/init.c

···
 			hw->wiphy->n_iface_combinations = 1;
 			hw->wiphy->max_scan_ssids = 255;
 			hw->wiphy->max_scan_ie_len = IEEE80211_MAX_DATA_LEN;
+			hw->wiphy->max_remain_on_channel_duration = 10000;
 		}
 	}
 

drivers/net/wireless/ath/ath9k/main.c

···
 	ath_chanctx_offchan_switch(sc, chan);
 }
 
+static 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.state = ATH_OFFCHANNEL_ROC_START;
+		ath_chanctx_offchan_switch(sc, sc->offchannel.roc_chan);
+	} else {
+		ath_chanctx_switch(sc, ath_chanctx_get_oper_chan(sc), NULL);
+		sc->offchannel.state = ATH_OFFCHANNEL_IDLE;
+		if (sc->ps_idle)
+			ath_cancel_work(sc);
+	}
+}
+
+static void ath_roc_complete(struct ath_softc *sc, bool abort)
+{
+	sc->offchannel.roc_vif = NULL;
+	sc->offchannel.roc_chan = NULL;
+	if (!abort)
+		ieee80211_remain_on_channel_expired(sc->hw);
+	ath_offchannel_next(sc);
+	ath9k_ps_restore(sc);
+}
+
 static void ath_scan_complete(struct ath_softc *sc, bool abort)
 {
 	struct ath_common *common = ath9k_hw_common(sc->sc_ah);
 
-	ath_chanctx_switch(sc, ath_chanctx_get_oper_chan(sc), NULL);
 	sc->offchannel.scan_req = NULL;
 	sc->offchannel.scan_vif = NULL;
 	sc->offchannel.state = ATH_OFFCHANNEL_IDLE;
 	ieee80211_scan_completed(sc->hw, abort);
 	clear_bit(ATH_OP_SCANNING, &common->op_flags);
+	ath_offchannel_next(sc);
 	ath9k_ps_restore(sc);
-
-	if (!sc->ps_idle)
-		return;
-
-	ath_cancel_work(sc);
 }
 
 static void ath_scan_send_probe(struct ath_softc *sc,
···
 
 void ath_offchannel_channel_change(struct ath_softc *sc)
 {
-	if (!sc->offchannel.scan_req)
-		return;
-
 	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 +
+			  msecs_to_jiffies(sc->offchannel.roc_duration));
+		ieee80211_ready_on_channel(sc->hw);
+		break;
+	case ATH_OFFCHANNEL_ROC_DONE:
+		ath_roc_complete(sc, false);
 		break;
 	default:
 		break;
···
 	struct ath_softc *sc = (struct ath_softc *)data;
 	struct ath_chanctx *ctx = ath_chanctx_get_oper_chan(sc);
 
-	if (!sc->offchannel.scan_req)
-		return;
-
 	switch (sc->offchannel.state) {
 	case ATH_OFFCHANNEL_PROBE_WAIT:
+		if (!sc->offchannel.scan_req)
+			return;
+
 		if (ctx->active) {
 			sc->offchannel.state = ATH_OFFCHANNEL_SUSPEND;
 			ath_chanctx_switch(sc, ctx, NULL);
···
 		}
 		/* 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_chanctx_switch(sc, ctx, NULL);
 		break;
 	default:
 		break;
···
 	sc->offchannel.scan_vif = vif;
 	sc->offchannel.scan_req = req;
 	sc->offchannel.scan_idx = 0;
-	sc->offchannel.chan.txpower = vif->bss_conf.txpower;
 
-	ath_scan_next_channel(sc);
+	if (sc->offchannel.state == ATH_OFFCHANNEL_IDLE)
+		ath_offchannel_next(sc);
 
 out:
 	mutex_unlock(&sc->mutex);
···
 	mutex_unlock(&sc->mutex);
 }
 
+static int ath9k_remain_on_channel(struct ieee80211_hw *hw,
+				   struct ieee80211_vif *vif,
+				   struct ieee80211_channel *chan, int duration,
+				   enum ieee80211_roc_type type)
+{
+	struct ath_softc *sc = hw->priv;
+	int ret = 0;
+
+	mutex_lock(&sc->mutex);
+
+	if (WARN_ON(sc->offchannel.roc_vif)) {
+		ret = -EBUSY;
+		goto out;
+	}
+
+	ath9k_ps_wakeup(sc);
+	sc->offchannel.roc_vif = vif;
+	sc->offchannel.roc_chan = chan;
+	sc->offchannel.roc_duration = duration;
+
+	if (sc->offchannel.state == ATH_OFFCHANNEL_IDLE)
+		ath_offchannel_next(sc);
+
+out:
+	mutex_unlock(&sc->mutex);
+
+	return ret;
+}
+
+static int ath9k_cancel_remain_on_channel(struct ieee80211_hw *hw)
+{
+	struct ath_softc *sc = hw->priv;
+
+	mutex_lock(&sc->mutex);
+
+	del_timer_sync(&sc->offchannel.timer);
+
+	if (sc->offchannel.roc_vif) {
+		if (sc->offchannel.state >= ATH_OFFCHANNEL_ROC_START)
+			ath_roc_complete(sc, true);
+	}
+
+	mutex_unlock(&sc->mutex);
+
+	return 0;
+}
+
 void ath9k_fill_chanctx_ops(void)
 {
 	if (!ath9k_use_chanctx)
···
 
 	ath9k_ops.hw_scan = ath9k_hw_scan;
 	ath9k_ops.cancel_hw_scan = ath9k_cancel_hw_scan;
+	ath9k_ops.remain_on_channel  = ath9k_remain_on_channel;
+	ath9k_ops.cancel_remain_on_channel = ath9k_cancel_remain_on_channel;
 }
 
 struct ieee80211_ops ath9k_ops = {

drivers/net/wireless/ath/ath9k/xmit.c

···
 	if (vif)
 		avp = (void *)vif->drv_priv;
 
+	if (info->flags & IEEE80211_TX_CTL_TX_OFFCHAN)
+		txctl->force_channel = true;
+
 	ret = ath_tx_prepare(hw, skb, txctl);
 	if (ret)
 	    return ret;
···
 	if (txctl->an && queue)
 		tid = ath_get_skb_tid(sc, txctl->an, skb);
 
-	if (info->flags & IEEE80211_TX_CTL_PS_RESPONSE) {
+	if (info->flags & (IEEE80211_TX_CTL_PS_RESPONSE |
+			   IEEE80211_TX_CTL_TX_OFFCHAN)) {
 		ath_txq_unlock(sc, txq);
 		txq = sc->tx.uapsdq;
 		ath_txq_lock(sc, txq);