libertas_tf: add get_survey callback in order to get channel noise

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

drivers/net/wireless/libertas_tf/libertas_tf.h

@@ -253,6 +253,9 @@ struct lbtf_private {
 	u8 fw_ready;
 	u8 surpriseremoved;
 	struct sk_buff_head bc_ps_buf;
+
+	/* Most recently reported noise in dBm */
+	s8 noise;
 };
 
 /* 802.11-related definitions */

drivers/net/wireless/libertas_tf/main.c

@@ -525,6 +525,22 @@ static void lbtf_op_bss_info_changed(struct ieee80211_hw *hw,
 	lbtf_deb_leave(LBTF_DEB_MACOPS);
 }
 
+static int lbtf_op_get_survey(struct ieee80211_hw *hw, int idx,
+				struct survey_info *survey)
+{
+	struct lbtf_private *priv = hw->priv;
+	struct ieee80211_conf *conf = &hw->conf;
+
+	if (idx != 0)
+		return -ENOENT;
+
+	survey->channel = conf->channel;
+	survey->filled = SURVEY_INFO_NOISE_DBM;
+	survey->noise = priv->noise;
+
+	return 0;
+}
+
 static const struct ieee80211_ops lbtf_ops = {
 	.tx			= lbtf_op_tx,
 	.start			= lbtf_op_start,
@@ -535,6 +551,7 @@ static const struct ieee80211_ops lbtf_ops = {
 	.prepare_multicast	= lbtf_op_prepare_multicast,
 	.configure_filter	= lbtf_op_configure_filter,
 	.bss_info_changed	= lbtf_op_bss_info_changed,
+	.get_survey		= lbtf_op_get_survey,
 };
 
 int lbtf_rx(struct lbtf_private *priv, struct sk_buff *skb)
@@ -555,6 +572,7 @@ int lbtf_rx(struct lbtf_private *priv, struct sk_buff *skb)
 	stats.freq = priv->cur_freq;
 	stats.band = IEEE80211_BAND_2GHZ;
 	stats.signal = prxpd->snr;
+	priv->noise = prxpd->nf;
 	/* Marvell rate index has a hole at value 4 */
 	if (prxpd->rx_rate > 4)
 		--prxpd->rx_rate;