diff --git a/src/ap/ap_drv_ops.h b/src/ap/ap_drv_ops.h
index cfc30ce..269f4ef 100644
--- a/src/ap/ap_drv_ops.h
+++ b/src/ap/ap_drv_ops.h
@@ -225,4 +225,14 @@ static inline void hostapd_drv_poll_client(struct hostapd_data *hapd,
 	hapd->driver->poll_client(hapd->drv_priv, own_addr, addr, qos);
 }
 
+static inline int hostapd_drv_get_survey(struct hostapd_data *hapd,
+					 unsigned int freq)
+{
+	if (hapd->driver == NULL)
+		return -1;
+        if (!hapd->driver->get_survey)
+		return -1;
+	return hapd->driver->get_survey(hapd->drv_priv, freq);
+}
+
 #endif /* AP_DRV_OPS */
diff --git a/src/ap/drv_callbacks.c b/src/ap/drv_callbacks.c
index fa4b5e4..e0f0491 100644
--- a/src/ap/drv_callbacks.c
+++ b/src/ap/drv_callbacks.c
@@ -715,6 +715,75 @@ static void hostapd_event_eapol_rx(struct hostapd_data *hapd, const u8 *src,
 }
 
 
+struct hostapd_channel_data * hostapd_get_mode_channel(
+	struct hostapd_iface *iface,
+	unsigned int freq)
+{
+	int i;
+	struct hostapd_channel_data *chan;
+
+	for (i = 0; i < iface->current_mode->num_channels; i++) {
+		chan = &iface->current_mode->channels[i];
+		if (!chan)
+			return NULL;
+		if ((unsigned int) chan->freq == freq)
+			return chan;
+	}
+
+	return NULL;
+}
+
+
+static void hostapd_update_nf(struct hostapd_iface *iface,
+			      struct hostapd_channel_data *chan,
+			      struct freq_survey *survey)
+{
+	if (!iface->chans_surveyed) {
+		chan->min_nf = survey->nf;
+		iface->lowest_nf = survey->nf;
+	} else {
+		if (dl_list_empty(&chan->survey_list))
+			chan->min_nf = survey->nf;
+		else if (survey->nf < chan->min_nf)
+			chan->min_nf = survey->nf;
+		if (survey->nf < iface->lowest_nf)
+			iface->lowest_nf = survey->nf;
+	}
+}
+
+
+static void hostapd_event_get_survey(struct hostapd_data *hapd,
+				     struct survey_results *survey_results)
+{
+	struct hostapd_iface *iface = hapd->iface;
+	struct freq_survey *survey, *tmp;
+	struct hostapd_channel_data *chan;
+
+	if (dl_list_empty(&survey_results->survey_list)) {
+		wpa_printf(MSG_DEBUG, "No survey data received");
+                return;
+	}
+
+	dl_list_for_each_safe(survey, tmp, &survey_results->survey_list,
+			      struct freq_survey, list) {
+		chan = hostapd_get_mode_channel(iface, survey->freq);
+		if (!chan)
+			continue;
+		if (chan->flag & HOSTAPD_CHAN_DISABLED)
+			continue;
+
+		dl_list_del(&survey->list);
+		dl_list_add_tail(&chan->survey_list, &survey->list);
+
+		hostapd_update_nf(iface, chan, survey);
+
+		iface->chans_surveyed++;
+	}
+
+	return;
+}
+
+
 void wpa_supplicant_event(void *ctx, enum wpa_event_type event,
 			  union wpa_event_data *data)
 {
@@ -856,6 +925,9 @@ void wpa_supplicant_event(void *ctx, enum wpa_event_type event,
 			hapd, data->connect_failed_reason.addr,
 			data->connect_failed_reason.code);
 		break;
+	case EVENT_SURVEY:
+		hostapd_event_get_survey(hapd, &data->survey_results);
+		break;
 	default:
 		wpa_printf(MSG_DEBUG, "Unknown event %d", event);
 		break;
diff --git a/src/ap/hostapd.h b/src/ap/hostapd.h
index c0b1306..ea70fe8 100644
--- a/src/ap/hostapd.h
+++ b/src/ap/hostapd.h
@@ -280,6 +280,15 @@ struct hostapd_iface {
 	int olbc_ht;
 
 	u16 ht_op_mode;
+
+	/* surveying helpers */
+
+	/* number of channels surveyed */
+	unsigned int chans_surveyed;
+
+	/* lowest observed noise floor in dBm */
+	s8 lowest_nf;
+
 	void (*scan_cb)(struct hostapd_iface *iface);
 };
 
diff --git a/src/drivers/driver.h b/src/drivers/driver.h
index d78bdd0..661f427 100644
--- a/src/drivers/driver.h
+++ b/src/drivers/driver.h
@@ -20,6 +20,7 @@
 #define WPA_SUPPLICANT_DRIVER_VERSION 4
 
 #include "common/defs.h"
+#include "utils/list.h"
 
 #define HOSTAPD_CHAN_DISABLED 0x00000001
 #define HOSTAPD_CHAN_PASSIVE_SCAN 0x00000002
@@ -55,9 +56,20 @@ struct hostapd_channel_data {
 	int flag;
 
 	/**
-	 * max_tx_power - maximum transmit power in dBm
+	 * max_tx_power - Maximum transmit power in dBm
 	 */
 	u8 max_tx_power;
+
+	/*
+	 * survey_list - Linked list of surveys
+	 */
+	struct dl_list survey_list;
+
+	/**
+	 * min_nf - Minimum observed noise floor, in dBm, based on all
+	 * surveyed channel data
+	 */
+	s8 min_nf;
 };
 
 #define HOSTAPD_MODE_FLAG_HT_INFO_KNOWN BIT(0)
@@ -2461,6 +2473,7 @@ struct wpa_driver_ops {
 	 * i.e., if it sets WPA_DRIVER_FLAGS_P2P_MGMT in
 	 * struct wpa_driver_capa.
 	 */
+
 	int (*p2p_sd_response)(void *priv, int freq, const u8 *dst,
 			       u8 dialog_token,
 			       const struct wpabuf *resp_tlvs);
@@ -2726,6 +2739,31 @@ struct wpa_driver_ops {
 	 * mode.
 	 */
 	int (*stop_ap)(void *priv);
+
+	/**
+	 * get_survey - Retrieve survey data
+	 * @priv: Private driver interface data
+	 * @freq: If set, survey data for the specified frequency is only
+	 *	being requested. If not set, all survey data is requested.
+	 * Returns: 0 on success, -1 on failure
+	 *
+	 * Use this to retrieve:
+	 *
+	 * - the observed channel noise floor
+	 * - the amount of time we have spent on the channel
+	 * - the amount of time during which we have spent on the channel that
+	 *   the radio has determined the medium is busy and we cannot
+	 *   transmit
+	 * - the amount of time we have spent receiving data
+	 * - the amount of time we have spent transmitting data
+	 *
+	 * This data can be used for spectrum heuristics. One example is
+	 * Automatic Channel Selection (ACS). The channel survey data is
+	 * kept on a linked list on the channel data, one entry is added
+	 * for each survey. The min_nf of the channel is updated for each
+	 * survey.
+	 */
+	int (*get_survey)(void *priv, unsigned int freq);
 };
 
 
@@ -3210,11 +3248,57 @@ enum wpa_event_type {
 	 *
 	 * The channel which was previously unavailable is now available again.
 	 */
-	EVENT_DFS_NOP_FINISHED
+	EVENT_DFS_NOP_FINISHED,
+
+	/*
+	* EVENT_SURVEY - Received survey data
+	*
+	* This event gets triggered when a driver query is issued for survey
+	* data and it's returned. The returned data is stored in
+	* struct survey_results. The results provide at most one survey
+	* entry for each frequency and at minimum will provide one survey
+	* entry for one frequency. The survey data can be os_malloc()'d and
+	* then os_free()'d, so the event callback must only copy data.
+	*/
+	EVENT_SURVEY
 };
 
 
 /**
+ * struct freq_survey - Channel survey info
+ *
+ * @ifidx: Interface index in which this survey was observed
+ * @freq: Center of frequency of the surveyed channel
+ * @nf: Channel noise floor in dBm
+ * @channel_time: Amount of time in ms the radio spent on the channel
+ * @channel_time_busy: Amount of time in ms the radio detected some signal
+ *     that indicated to the radio the channel was not clear
+ * @channel_time_rx: Amount of time the radio spent receiving data
+ * @channel_time_tx: Amount of time the radio spent transmitting data
+ * @filled: bitmask indicating which fields have been reported, see
+ *     SURVEY_HAS_* defines.
+ * @list: Internal list pointers
+ */
+struct freq_survey {
+	u32 ifidx;
+	unsigned int freq;
+	s8 nf;
+	u64 channel_time;
+	u64 channel_time_busy;
+	u64 channel_time_rx;
+	u64 channel_time_tx;
+	unsigned int filled;
+	struct dl_list list;
+};
+
+#define SURVEY_HAS_NF BIT(0)
+#define SURVEY_HAS_CHAN_TIME BIT(1)
+#define SURVEY_HAS_CHAN_TIME_BUSY BIT(2)
+#define SURVEY_HAS_CHAN_TIME_RX BIT(3)
+#define SURVEY_HAS_CHAN_TIME_TX BIT(4)
+
+
+/**
  * union wpa_event_data - Additional data for wpa_supplicant_event() calls
  */
 union wpa_event_data {
@@ -3856,6 +3940,17 @@ union wpa_event_data {
 	struct dfs_event {
 		int freq;
 	} dfs_event;
+
+	/**
+	 * survey_results - Survey result data for EVENT_SURVEY
+	 * @freq_filter: Requested frequency survey filter, 0 if request
+	 *	was for all survey data
+	 * @survey_list: Linked list of survey data
+	 */
+	struct survey_results {
+		unsigned int freq_filter;
+		struct dl_list survey_list; /* struct freq_survey */
+	} survey_results;
 };
 
 /**
diff --git a/src/drivers/driver_common.c b/src/drivers/driver_common.c
index 12ccc14..8d1d22e 100644
--- a/src/drivers/driver_common.c
+++ b/src/drivers/driver_common.c
@@ -84,6 +84,7 @@ const char * event_to_string(enum wpa_event_type event)
 	E2S(DFS_CAC_FINISHED);
 	E2S(DFS_CAC_ABORTED);
 	E2S(DFS_NOP_FINISHED);
+	E2S(SURVEY);
 	}
 
 	return "UNKNOWN";
diff --git a/src/drivers/driver_nl80211.c b/src/drivers/driver_nl80211.c
index 2f30cda..f2fadd2 100644
--- a/src/drivers/driver_nl80211.c
+++ b/src/drivers/driver_nl80211.c
@@ -9944,6 +9944,190 @@ static int nl80211_flush_pmkid(void *priv)
 }
 
 
+static void clean_survey_results(struct survey_results *survey_results)
+{
+	struct freq_survey *survey, *tmp;
+
+	if (dl_list_empty(&survey_results->survey_list))
+		return;
+
+	dl_list_for_each_safe(survey, tmp, &survey_results->survey_list,
+			      struct freq_survey, list) {
+		dl_list_del(&survey->list);
+		os_free(survey);
+	}
+}
+
+
+static void add_survey(struct nlattr **sinfo, u32 ifidx,
+		       struct dl_list *survey_list)
+{
+	struct freq_survey *survey;
+
+	survey = os_zalloc(sizeof(struct freq_survey));
+	if  (!survey)
+		return;
+
+	survey->ifidx = ifidx;
+	survey->freq = nla_get_u32(sinfo[NL80211_SURVEY_INFO_FREQUENCY]);
+	survey->filled = 0;
+
+	if (sinfo[NL80211_SURVEY_INFO_NOISE]) {
+		survey->nf = (int8_t)
+			nla_get_u8(sinfo[NL80211_SURVEY_INFO_NOISE]);
+		survey->filled |= SURVEY_HAS_NF;
+	}
+
+	if (sinfo[NL80211_SURVEY_INFO_CHANNEL_TIME]) {
+		survey->channel_time =
+			nla_get_u64(sinfo[NL80211_SURVEY_INFO_CHANNEL_TIME]);
+		survey->filled |= SURVEY_HAS_CHAN_TIME;
+	}
+
+	if (sinfo[NL80211_SURVEY_INFO_CHANNEL_TIME_BUSY]) {
+		survey->channel_time_busy =
+			nla_get_u64(sinfo[NL80211_SURVEY_INFO_CHANNEL_TIME_BUSY]);
+		survey->filled |= SURVEY_HAS_CHAN_TIME_BUSY;
+	}
+
+	if (sinfo[NL80211_SURVEY_INFO_CHANNEL_TIME_RX]) {
+		survey->channel_time_rx =
+			nla_get_u64(sinfo[NL80211_SURVEY_INFO_CHANNEL_TIME_RX]);
+		survey->filled |= SURVEY_HAS_CHAN_TIME_RX;
+	}
+
+	if (sinfo[NL80211_SURVEY_INFO_CHANNEL_TIME_TX]) {
+		survey->channel_time_tx =
+			nla_get_u64(sinfo[NL80211_SURVEY_INFO_CHANNEL_TIME_TX]);
+		survey->filled |= SURVEY_HAS_CHAN_TIME_TX;
+	}
+
+	wpa_printf(MSG_DEBUG, "nl80211: Freq survey dump event (freq=%d MHz "
+		   "noise=%d channel_time=%ld busy_time=%ld tx_time=%ld "
+		   "rx_time=%ld filled=%04x)",
+		   survey->freq,
+		   survey->nf,
+		   (unsigned long int) survey->channel_time,
+		   (unsigned long int) survey->channel_time_busy,
+		   (unsigned long int) survey->channel_time_tx,
+		   (unsigned long int) survey->channel_time_rx,
+		   survey->filled);
+
+	dl_list_add_tail(survey_list, &survey->list);
+}
+
+
+static int check_survey_ok(struct nlattr **sinfo, u32 surveyed_freq,
+			   unsigned int freq_filter)
+{
+	if (!freq_filter)
+		return 1;
+
+	if (freq_filter == surveyed_freq)
+		return 1;
+
+	return 0;
+}
+
+
+static int survey_handler(struct nl_msg *msg, void *arg)
+{
+	struct nlattr *tb[NL80211_ATTR_MAX + 1];
+	struct genlmsghdr *gnlh = nlmsg_data(nlmsg_hdr(msg));
+	struct nlattr *sinfo[NL80211_SURVEY_INFO_MAX + 1];
+	struct survey_results *survey_results;
+	u32 surveyed_freq = 0;
+	u32 ifidx;
+
+	static struct nla_policy survey_policy[NL80211_SURVEY_INFO_MAX + 1] = {
+		[NL80211_SURVEY_INFO_FREQUENCY] = { .type = NLA_U32 },
+		[NL80211_SURVEY_INFO_NOISE] = { .type = NLA_U8 },
+	};
+
+	survey_results = (struct survey_results *) arg;
+
+	nla_parse(tb, NL80211_ATTR_MAX, genlmsg_attrdata(gnlh, 0),
+		  genlmsg_attrlen(gnlh, 0), NULL);
+
+	ifidx = nla_get_u32(tb[NL80211_ATTR_IFINDEX]);
+
+	if (!tb[NL80211_ATTR_SURVEY_INFO])
+		return NL_SKIP;
+
+	if (nla_parse_nested(sinfo, NL80211_SURVEY_INFO_MAX,
+			     tb[NL80211_ATTR_SURVEY_INFO],
+			     survey_policy))
+		return NL_SKIP;
+
+	if (!sinfo[NL80211_SURVEY_INFO_FREQUENCY]) {
+		wpa_printf(MSG_ERROR, "nl80211: invalid survey data");
+		return NL_SKIP;
+	}
+
+	surveyed_freq = nla_get_u32(sinfo[NL80211_SURVEY_INFO_FREQUENCY]);
+
+	if (!check_survey_ok(sinfo, surveyed_freq,
+			     survey_results->freq_filter))
+		return NL_SKIP;
+
+	if (survey_results->freq_filter &&
+	    survey_results->freq_filter != surveyed_freq) {
+		wpa_printf(MSG_EXCESSIVE, "nl80211: Ignoring survey data "
+			   "for freq %d MHz", surveyed_freq);
+		return NL_SKIP;
+	}
+
+	add_survey(sinfo, ifidx, &survey_results->survey_list);
+
+	return NL_SKIP;
+}
+
+
+static int wpa_driver_nl80211_get_survey(void *priv, unsigned int freq)
+{
+	struct i802_bss *bss = priv;
+	struct wpa_driver_nl80211_data *drv = bss->drv;
+	struct nl_msg *msg;
+	int err = -ENOBUFS;
+	union wpa_event_data data;
+	struct survey_results *survey_results;
+
+	os_memset(&data, 0, sizeof(data));
+	survey_results = &data.survey_results;
+
+	dl_list_init(&survey_results->survey_list);
+
+	msg = nlmsg_alloc();
+	if (!msg)
+		goto nla_put_failure;
+
+	nl80211_cmd(drv, msg, NLM_F_DUMP, NL80211_CMD_GET_SURVEY);
+
+	NLA_PUT_U32(msg, NL80211_ATTR_IFINDEX, drv->ifindex);
+
+	if (freq)
+		data.survey_results.freq_filter = freq;
+
+	do {
+		err = send_and_recv_msgs(drv, msg, survey_handler,
+					 survey_results);
+	} while (err > 0);
+
+	if (err) {
+		wpa_printf(MSG_ERROR, "nl80211: Failed to process survey "
+			   "data");
+		goto out_clean;
+	}
+
+	wpa_supplicant_event(drv->ctx, EVENT_SURVEY, &data);
+
+out_clean:
+	clean_survey_results(survey_results);
+nla_put_failure:
+	return err;
+}
+
+
 static void nl80211_set_rekey_info(void *priv, const u8 *kek, const u8 *kck,
 				   const u8 *replay_ctr)
 {
@@ -10570,4 +10754,5 @@ const struct wpa_driver_ops wpa_driver_nl80211_ops = {
 #endif /* CONFIG_TDLS */
 	.update_ft_ies = wpa_driver_nl80211_update_ft_ies,
 	.get_mac_addr = wpa_driver_nl80211_get_macaddr,
+	.get_survey = wpa_driver_nl80211_get_survey,
 };
