ath9k: enable CSA functionality in ath9k

CSA is only enabled for one interface, but the same limitation applies
for mac80211 too. It checks whether the beacon has been sent (different
approaches for non-EDMA-enabled and EDMA-enabled devices), and completes
the channel switch after that.

Signed-off-by: Simon Wunderlich <siwu@hrz.tu-chemnitz.de>
Signed-off-by: Mathias Kretschmer <mathias.kretschmer@fokus.fraunhofer.de>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

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

@@ -420,6 +420,7 @@ void ath9k_beacon_assign_slot(struct ath_softc *sc, struct ieee80211_vif *vif);
 void ath9k_beacon_remove_slot(struct ath_softc *sc, struct ieee80211_vif *vif);
 void ath9k_set_tsfadjust(struct ath_softc *sc, struct ieee80211_vif *vif);
 void ath9k_set_beacon(struct ath_softc *sc);
+bool ath9k_csa_is_finished(struct ath_softc *sc);
 
 /*******************/
 /* Link Monitoring */
@@ -756,6 +757,7 @@ struct ath_softc {
 #endif
 
 	struct ath_descdma txsdma;
+	struct ieee80211_vif *csa_vif;
 
 	struct ath_ant_comb ant_comb;
 	u8 ant_tx, ant_rx;

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

@@ -291,6 +291,23 @@ void ath9k_set_tsfadjust(struct ath_softc *sc, struct ieee80211_vif *vif)
 		(unsigned long long)tsfadjust, avp->av_bslot);
 }
 
+bool ath9k_csa_is_finished(struct ath_softc *sc)
+{
+	struct ieee80211_vif *vif;
+
+	vif = sc->csa_vif;
+	if (!vif || !vif->csa_active)
+		return false;
+
+	if (!ieee80211_csa_is_complete(vif))
+		return false;
+
+	ieee80211_csa_finish(vif);
+
+	sc->csa_vif = NULL;
+	return true;
+}
+
 void ath9k_beacon_tasklet(unsigned long data)
 {
 	struct ath_softc *sc = (struct ath_softc *)data;
@@ -336,6 +353,10 @@ void ath9k_beacon_tasklet(unsigned long data)
 		return;
 	}
 
+	/* EDMA devices check that in the tx completion function. */
+	if (!edma && ath9k_csa_is_finished(sc))
+		return;
+
 	slot = ath9k_beacon_choose_slot(sc);
 	vif = sc->beacon.bslot[slot];
 

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

@@ -861,6 +861,7 @@ void ath9k_set_hw_capab(struct ath_softc *sc, struct ieee80211_hw *hw)
 	hw->wiphy->flags |= WIPHY_FLAG_SUPPORTS_TDLS;
 	hw->wiphy->flags |= WIPHY_FLAG_HAS_REMAIN_ON_CHANNEL;
 	hw->wiphy->flags |= WIPHY_FLAG_SUPPORTS_5_10_MHZ;
+	hw->wiphy->flags |= WIPHY_FLAG_HAS_CHANNEL_SWITCH;
 
 #ifdef CONFIG_PM_SLEEP
 	if ((ah->caps.hw_caps & ATH9K_HW_WOW_DEVICE_CAPABLE) &&

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

@@ -1032,6 +1032,9 @@ static void ath9k_remove_interface(struct ieee80211_hw *hw,
 	if (ath9k_uses_beacons(vif->type))
 		ath9k_beacon_remove_slot(sc, vif);
 
+	if (sc->csa_vif == vif)
+		sc->csa_vif = NULL;
+
 	ath9k_ps_wakeup(sc);
 	ath9k_calculate_summary_state(hw, NULL);
 	ath9k_ps_restore(sc);
@@ -2318,6 +2321,19 @@ static void ath9k_sw_scan_complete(struct ieee80211_hw *hw)
 	clear_bit(SC_OP_SCANNING, &sc->sc_flags);
 }
 
+static void ath9k_channel_switch_beacon(struct ieee80211_hw *hw,
+					struct ieee80211_vif *vif,
+					struct cfg80211_chan_def *chandef)
+{
+	struct ath_softc *sc = hw->priv;
+
+	/* mac80211 does not support CSA in multi-if cases (yet) */
+	if (WARN_ON(sc->csa_vif))
+		return;
+
+	sc->csa_vif = vif;
+}
+
 struct ieee80211_ops ath9k_ops = {
 	.tx 		    = ath9k_tx,
 	.start 		    = ath9k_start,
@@ -2365,4 +2381,5 @@ struct ieee80211_ops ath9k_ops = {
 #endif
 	.sw_scan_start	    = ath9k_sw_scan_start,
 	.sw_scan_complete   = ath9k_sw_scan_complete,
+	.channel_switch_beacon     = ath9k_channel_switch_beacon,
 };

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

@@ -2559,6 +2559,8 @@ void ath_tx_edma_tasklet(struct ath_softc *sc)
 		if (ts.qid == sc->beacon.beaconq) {
 			sc->beacon.tx_processed = true;
 			sc->beacon.tx_last = !(ts.ts_status & ATH9K_TXERR_MASK);
+
+			ath9k_csa_is_finished(sc);
 			continue;
 		}