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>
diff --git a/drivers/net/wireless/ath/ath9k/ath9k.h b/drivers/net/wireless/ath/ath9k/ath9k.h
index df1c495..8519e75 100644
--- a/drivers/net/wireless/ath/ath9k/ath9k.h
+++ b/drivers/net/wireless/ath/ath9k/ath9k.h
@@ -420,6 +420,7 @@
 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 @@
 #endif
 
 	struct ath_descdma txsdma;
+	struct ieee80211_vif *csa_vif;
 
 	struct ath_ant_comb ant_comb;
 	u8 ant_tx, ant_rx;
diff --git a/drivers/net/wireless/ath/ath9k/beacon.c b/drivers/net/wireless/ath/ath9k/beacon.c
index 1a17732..b5c16b3a 100644
--- a/drivers/net/wireless/ath/ath9k/beacon.c
+++ b/drivers/net/wireless/ath/ath9k/beacon.c
@@ -291,6 +291,23 @@
 		(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 @@
 		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];
 
diff --git a/drivers/net/wireless/ath/ath9k/init.c b/drivers/net/wireless/ath/ath9k/init.c
index 60bb4d6..abf1eb5 100644
--- a/drivers/net/wireless/ath/ath9k/init.c
+++ b/drivers/net/wireless/ath/ath9k/init.c
@@ -861,6 +861,7 @@
 	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) &&
diff --git a/drivers/net/wireless/ath/ath9k/main.c b/drivers/net/wireless/ath/ath9k/main.c
index ba382a8..ac9f18f 100644
--- a/drivers/net/wireless/ath/ath9k/main.c
+++ b/drivers/net/wireless/ath/ath9k/main.c
@@ -1032,6 +1032,9 @@
 	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 @@
 	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 @@
 #endif
 	.sw_scan_start	    = ath9k_sw_scan_start,
 	.sw_scan_complete   = ath9k_sw_scan_complete,
+	.channel_switch_beacon     = ath9k_channel_switch_beacon,
 };
diff --git a/drivers/net/wireless/ath/ath9k/xmit.c b/drivers/net/wireless/ath/ath9k/xmit.c
index 7223e30..35b515f 100644
--- a/drivers/net/wireless/ath/ath9k/xmit.c
+++ b/drivers/net/wireless/ath/ath9k/xmit.c
@@ -2559,6 +2559,8 @@
 		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;
 		}