cfg80211: add channel utilization stats to the survey command

Using these, user space can calculate a relative channel utilization
with arbitrary intervals by regularly taking snapshots of the survey
results.

Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
index f920a06..24d5b58 100644
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h
@@ -294,6 +294,11 @@
  *
  * @SURVEY_INFO_NOISE_DBM: noise (in dBm) was filled in
  * @SURVEY_INFO_IN_USE: channel is currently being used
+ * @SURVEY_INFO_CHANNEL_TIME: channel active time (in ms) was filled in
+ * @SURVEY_INFO_CHANNEL_TIME_BUSY: channel busy time was filled in
+ * @SURVEY_INFO_CHANNEL_TIME_EXT_BUSY: extension channel busy time was filled in
+ * @SURVEY_INFO_CHANNEL_TIME_RX: channel receive time was filled in
+ * @SURVEY_INFO_CHANNEL_TIME_TX: channel transmit time was filled in
  *
  * Used by the driver to indicate which info in &struct survey_info
  * it has filled in during the get_survey().
@@ -301,6 +306,11 @@
 enum survey_info_flags {
 	SURVEY_INFO_NOISE_DBM = 1<<0,
 	SURVEY_INFO_IN_USE = 1<<1,
+	SURVEY_INFO_CHANNEL_TIME = 1<<2,
+	SURVEY_INFO_CHANNEL_TIME_BUSY = 1<<3,
+	SURVEY_INFO_CHANNEL_TIME_EXT_BUSY = 1<<4,
+	SURVEY_INFO_CHANNEL_TIME_RX = 1<<5,
+	SURVEY_INFO_CHANNEL_TIME_TX = 1<<6,
 };
 
 /**
@@ -310,6 +320,11 @@
  * @filled: bitflag of flags from &enum survey_info_flags
  * @noise: channel noise in dBm. This and all following fields are
  *     optional
+ * @channel_time: amount of time in ms the radio spent on the channel
+ * @channel_time_busy: amount of time the primary channel was sensed busy
+ * @channel_time_ext_busy: amount of time the extension channel was sensed busy
+ * @channel_time_rx: amount of time the radio spent receiving data
+ * @channel_time_tx: amount of time the radio spent transmitting data
  *
  * Used by dump_survey() to report back per-channel survey information.
  *
@@ -318,6 +333,11 @@
  */
 struct survey_info {
 	struct ieee80211_channel *channel;
+	u64 channel_time;
+	u64 channel_time_busy;
+	u64 channel_time_ext_busy;
+	u64 channel_time_rx;
+	u64 channel_time_tx;
 	u32 filled;
 	s8 noise;
 };