ath10k: implement get_survey()

This implements a limited subset of what can be
reported in the survey dump.

This can be used for assessing approximate channel
load, e.g. for automatic channel selection.

Signed-off-by: Michal Kazior <michal.kazior@tieto.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>
diff --git a/drivers/net/wireless/ath/ath10k/mac.c b/drivers/net/wireless/ath/ath10k/mac.c
index 5784337..9ea31f8 100644
--- a/drivers/net/wireless/ath/ath10k/mac.c
+++ b/drivers/net/wireless/ath/ath10k/mac.c
@@ -2934,6 +2934,41 @@
 	mutex_unlock(&ar->conf_mutex);
 }
 
+static int ath10k_get_survey(struct ieee80211_hw *hw, int idx,
+			     struct survey_info *survey)
+{
+	struct ath10k *ar = hw->priv;
+	struct ieee80211_supported_band *sband;
+	struct survey_info *ar_survey = &ar->survey[idx];
+	int ret = 0;
+
+	mutex_lock(&ar->conf_mutex);
+
+	sband = hw->wiphy->bands[IEEE80211_BAND_2GHZ];
+	if (sband && idx >= sband->n_channels) {
+		idx -= sband->n_channels;
+		sband = NULL;
+	}
+
+	if (!sband)
+		sband = hw->wiphy->bands[IEEE80211_BAND_5GHZ];
+
+	if (!sband || idx >= sband->n_channels) {
+		ret = -ENOENT;
+		goto exit;
+	}
+
+	spin_lock_bh(&ar->data_lock);
+	memcpy(survey, ar_survey, sizeof(*survey));
+	spin_unlock_bh(&ar->data_lock);
+
+	survey->channel = &sband->channels[idx];
+
+exit:
+	mutex_unlock(&ar->conf_mutex);
+	return ret;
+}
+
 static const struct ieee80211_ops ath10k_ops = {
 	.tx				= ath10k_tx,
 	.start				= ath10k_start,
@@ -2955,6 +2990,7 @@
 	.flush				= ath10k_flush,
 	.tx_last_beacon			= ath10k_tx_last_beacon,
 	.restart_complete		= ath10k_restart_complete,
+	.get_survey			= ath10k_get_survey,
 #ifdef CONFIG_PM
 	.suspend			= ath10k_suspend,
 	.resume				= ath10k_resume,