cfg80211/nl80211: add CAC_STARTED event

CAC_STARTED event is needed for DFS offload feature and
should be generated by driver/HW if DFS_OFFLOAD is enabled.
Signed-off-by: Dmitry Lebed <dlebed@quantenna.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

include/uapi/linux/nl80211.h

@@ -5204,6 +5204,8 @@ enum nl80211_smps_mode {
  *	non-operating channel is expired and no longer valid. New CAC must
  *	be done on this channel before starting the operation. This is not
  *	applicable for ETSI dfs domain where pre-CAC is valid for ever.
+ * @NL80211_RADAR_CAC_STARTED: Channel Availability Check has been started,
+ *	should be generated by HW if NL80211_EXT_FEATURE_DFS_OFFLOAD is enabled.
  */
 enum nl80211_radar_event {
 	NL80211_RADAR_DETECTED,
@@ -5211,6 +5213,7 @@ enum nl80211_radar_event {
 	NL80211_RADAR_CAC_ABORTED,
 	NL80211_RADAR_NOP_FINISHED,
 	NL80211_RADAR_PRE_CAC_EXPIRED,
+	NL80211_RADAR_CAC_STARTED,
 };
 
 /**

net/wireless/mlme.c

@@ -888,14 +888,17 @@ void cfg80211_cac_event(struct net_device *netdev,
 		       sizeof(struct cfg80211_chan_def));
 		queue_work(cfg80211_wq, &rdev->propagate_cac_done_wk);
 		cfg80211_sched_dfs_chan_update(rdev);
-		break;
+		/* fall through */
 	case NL80211_RADAR_CAC_ABORTED:
+		wdev->cac_started = false;
+		break;
+	case NL80211_RADAR_CAC_STARTED:
+		wdev->cac_started = true;
 		break;
 	default:
 		WARN_ON(1);
 		return;
 	}
-	wdev->cac_started = false;
 
 	nl80211_radar_notify(rdev, chandef, event, netdev, gfp);
 }