ath5k: Implement antenna control

* Add code to support the various antenna scenarios supported by hw

 * For now hardcode the default scenario (single or dual omnis with
 tx/rx diversity working and tx antenna handled by session -hw keeps
 track on which antenna it got ack from each ap/station and maps each
 ap/station to one of the antennas-).

 Signed-off-by: Nick Kossifidis <mickflemm@gmail.com>
 Signed-off-by: Bob Copeland <me@bobcopeland.com>

Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 50 insertions, 16 deletions

diff --git a/drivers/net/wireless/ath/ath5k/base.c b/drivers/net/wireless/ath/ath5k/base.c
index 912ffc5c0203..6789c5dfcc76 100644
--- a/drivers/net/wireless/ath/ath5k/base.c
+++ b/drivers/net/wireless/ath/ath5k/base.c
@@ -1279,7 +1279,7 @@ ath5k_txbuf_setup(struct ath5k_softc *sc, struct ath5k_buf *bf)
 		ieee80211_get_hdrlen_from_skb(skb), AR5K_PKT_TYPE_NORMAL,
 		(sc->power_level * 2),
 		hw_rate,
-		info->control.rates[0].count, keyidx, 0, flags,
+		info->control.rates[0].count, keyidx, ah->ah_tx_ant, flags,
 		cts_rate, duration);
 	if (ret)
 		goto err_unmap;
@@ -2009,7 +2009,8 @@ ath5k_beacon_setup(struct ath5k_softc *sc, struct ath5k_buf *bf)
 	struct	ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
 	struct ath5k_hw *ah = sc->ah;
 	struct ath5k_desc *ds;
-	int ret, antenna = 0;
+	int ret = 0;
+	u8 antenna;
 	u32 flags;
 
 	bf->skbaddr = pci_map_single(sc->pdev, skb->data, skb->len,
@@ -2023,23 +2024,35 @@ ath5k_beacon_setup(struct ath5k_softc *sc, struct ath5k_buf *bf)
 	}
 
 	ds = bf->desc;
+	antenna = ah->ah_tx_ant;
 
 	flags = AR5K_TXDESC_NOACK;
 	if (sc->opmode == NL80211_IFTYPE_ADHOC && ath5k_hw_hasveol(ah)) {
 		ds->ds_link = bf->daddr;	/* self-linked */
 		flags |= AR5K_TXDESC_VEOL;
-		/*
-		 * Let hardware handle antenna switching if txantenna is not set
-		 */
-	} else {
+	} else
 		ds->ds_link = 0;
-		/*
-		 * Switch antenna every 4 beacons if txantenna is not set
-		 * XXX assumes two antennas
-		 */
-		if (antenna == 0)
-			antenna = sc->bsent & 4 ? 2 : 1;
-	}
+
+	/*
+	 * If we use multiple antennas on AP and use
+	 * the Sectored AP scenario, switch antenna every
+	 * 4 beacons to make sure everybody hears our AP.
+	 * When a client tries to associate, hw will keep
+	 * track of the tx antenna to be used for this client
+	 * automaticaly, based on ACKed packets.
+	 *
+	 * Note: AP still listens and transmits RTS on the
+	 * default antenna which is supposed to be an omni.
+	 *
+	 * Note2: On sectored scenarios it's possible to have
+	 * multiple antennas (1omni -the default- and 14 sectors)
+	 * so if we choose to actually support this mode we need
+	 * to allow user to set how many antennas we have and tweak
+	 * the code below to send beacons on all of them.
+	 */
+	if (ah->ah_ant_mode == AR5K_ANTMODE_SECTOR_AP)
+		antenna = sc->bsent & 4 ? 2 : 1;
+
 
 	/* FIXME: If we are in g mode and rate is a CCK rate
 	 * subtract ah->ah_txpower.txp_cck_ofdm_pwr_delta
@@ -2752,12 +2765,16 @@ ath5k_config(struct ieee80211_hw *hw, u32 changed)
 	struct ath5k_softc *sc = hw->priv;
 	struct ath5k_hw *ah = sc->ah;
 	struct ieee80211_conf *conf = &hw->conf;
-	int ret;
+	int ret = 0;
 
 	mutex_lock(&sc->lock);
 
 	sc->bintval = conf->beacon_int;
 
+	ret = ath5k_chan_set(sc, conf->channel);
+	if (ret < 0)
+		return ret;
+
 	if ((changed & IEEE80211_CONF_CHANGE_POWER) &&
 	(sc->power_level != conf->power_level)) {
 		sc->power_level = conf->power_level;
@@ -2766,10 +2783,27 @@ ath5k_config(struct ieee80211_hw *hw, u32 changed)
 		ath5k_hw_set_txpower_limit(ah, (conf->power_level * 2));
 	}
 
-	ret = ath5k_chan_set(sc, conf->channel);
+	/* TODO:
+	 * 1) Move this on config_interface and handle each case
+	 * separately eg. when we have only one STA vif, use
+	 * AR5K_ANTMODE_SINGLE_AP
+	 *
+	 * 2) Allow the user to change antenna mode eg. when only
+	 * one antenna is present
+	 *
+	 * 3) Allow the user to set default/tx antenna when possible
+	 *
+	 * 4) Default mode should handle 90% of the cases, together
+	 * with fixed a/b and single AP modes we should be able to
+	 * handle 99%. Sectored modes are extreme cases and i still
+	 * haven't found a usage for them. If we decide to support them,
+	 * then we must allow the user to set how many tx antennas we
+	 * have available
+	 */
+	ath5k_hw_set_antenna_mode(ah, AR5K_ANTMODE_DEFAULT);
 
 	mutex_unlock(&sc->lock);
-	return ret;
+	return 0;
 }
 
 #define SUPPORTED_FIF_FLAGS \