diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index d29a461..c1e18cc 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -552,9 +552,16 @@
 	if ((chan->flags & IEEE80211_CHAN_NO_IBSS) &&
 	    nla_put_flag(msg, NL80211_FREQUENCY_ATTR_NO_IBSS))
 		goto nla_put_failure;
-	if ((chan->flags & IEEE80211_CHAN_RADAR) &&
-	    nla_put_flag(msg, NL80211_FREQUENCY_ATTR_RADAR))
-		goto nla_put_failure;
+	if (chan->flags & IEEE80211_CHAN_RADAR) {
+		u32 time = elapsed_jiffies_msecs(chan->dfs_state_entered);
+		if (nla_put_flag(msg, NL80211_FREQUENCY_ATTR_RADAR))
+			goto nla_put_failure;
+		if (nla_put_u32(msg, NL80211_FREQUENCY_ATTR_DFS_STATE,
+				chan->dfs_state))
+			goto nla_put_failure;
+		if (nla_put_u32(msg, NL80211_FREQUENCY_ATTR_DFS_TIME, time))
+			goto nla_put_failure;
+	}
 
 	if (nla_put_u32(msg, NL80211_FREQUENCY_ATTR_MAX_TX_POWER,
 			DBM_TO_MBM(chan->max_power)))
@@ -2775,6 +2782,7 @@
 	struct wireless_dev *wdev = dev->ieee80211_ptr;
 	struct cfg80211_ap_settings params;
 	int err;
+	u8 radar_detect_width = 0;
 
 	if (dev->ieee80211_ptr->iftype != NL80211_IFTYPE_AP &&
 	    dev->ieee80211_ptr->iftype != NL80211_IFTYPE_P2P_GO)
@@ -2893,9 +2901,19 @@
 	if (!cfg80211_reg_can_beacon(&rdev->wiphy, &params.chandef))
 		return -EINVAL;
 
+	err = cfg80211_chandef_dfs_required(wdev->wiphy, &params.chandef);
+	if (err < 0)
+		return err;
+	if (err) {
+		radar_detect_width = BIT(params.chandef.width);
+		params.radar_required = true;
+	}
+
 	mutex_lock(&rdev->devlist_mtx);
-	err = cfg80211_can_use_chan(rdev, wdev, params.chandef.chan,
-				    CHAN_MODE_SHARED);
+	err = cfg80211_can_use_iftype_chan(rdev, wdev, wdev->iftype,
+					   params.chandef.chan,
+					   CHAN_MODE_SHARED,
+					   radar_detect_width);
 	mutex_unlock(&rdev->devlist_mtx);
 
 	if (err)
@@ -5055,6 +5073,54 @@
 	return err;
 }
 
+static int nl80211_start_radar_detection(struct sk_buff *skb,
+					 struct genl_info *info)
+{
+	struct cfg80211_registered_device *rdev = info->user_ptr[0];
+	struct net_device *dev = info->user_ptr[1];
+	struct wireless_dev *wdev = dev->ieee80211_ptr;
+	struct cfg80211_chan_def chandef;
+	int err;
+
+	err = nl80211_parse_chandef(rdev, info, &chandef);
+	if (err)
+		return err;
+
+	if (wdev->cac_started)
+		return -EBUSY;
+
+	err = cfg80211_chandef_dfs_required(wdev->wiphy, &chandef);
+	if (err < 0)
+		return err;
+
+	if (err == 0)
+		return -EINVAL;
+
+	if (chandef.chan->dfs_state != NL80211_DFS_USABLE)
+		return -EINVAL;
+
+	if (!rdev->ops->start_radar_detection)
+		return -EOPNOTSUPP;
+
+	mutex_lock(&rdev->devlist_mtx);
+	err = cfg80211_can_use_iftype_chan(rdev, wdev, wdev->iftype,
+					   chandef.chan, CHAN_MODE_SHARED,
+					   BIT(chandef.width));
+	if (err)
+		goto err_locked;
+
+	err = rdev->ops->start_radar_detection(&rdev->wiphy, dev, &chandef);
+	if (!err) {
+		wdev->channel = chandef.chan;
+		wdev->cac_started = true;
+		wdev->cac_start_time = jiffies;
+	}
+err_locked:
+	mutex_unlock(&rdev->devlist_mtx);
+
+	return err;
+}
+
 static int nl80211_send_bss(struct sk_buff *msg, struct netlink_callback *cb,
 			    u32 seq, int flags,
 			    struct cfg80211_registered_device *rdev,
@@ -8305,6 +8371,14 @@
 		.internal_flags = NL80211_FLAG_NEED_NETDEV |
 				  NL80211_FLAG_NEED_RTNL,
 	},
+	{
+		.cmd = NL80211_CMD_RADAR_DETECT,
+		.doit = nl80211_start_radar_detection,
+		.policy = nl80211_policy,
+		.flags = GENL_ADMIN_PERM,
+		.internal_flags = NL80211_FLAG_NEED_NETDEV_UP |
+				  NL80211_FLAG_NEED_RTNL,
+	},
 };
 
 static struct genl_multicast_group nl80211_mlme_mcgrp = {
@@ -9502,6 +9576,57 @@
 }
 
 void
+nl80211_radar_notify(struct cfg80211_registered_device *rdev,
+		     struct cfg80211_chan_def *chandef,
+		     enum nl80211_radar_event event,
+		     struct net_device *netdev, gfp_t gfp)
+{
+	struct sk_buff *msg;
+	void *hdr;
+
+	msg = nlmsg_new(NLMSG_DEFAULT_SIZE, gfp);
+	if (!msg)
+		return;
+
+	hdr = nl80211hdr_put(msg, 0, 0, 0, NL80211_CMD_RADAR_DETECT);
+	if (!hdr) {
+		nlmsg_free(msg);
+		return;
+	}
+
+	if (nla_put_u32(msg, NL80211_ATTR_WIPHY, rdev->wiphy_idx))
+		goto nla_put_failure;
+
+	/* NOP and radar events don't need a netdev parameter */
+	if (netdev) {
+		struct wireless_dev *wdev = netdev->ieee80211_ptr;
+
+		if (nla_put_u32(msg, NL80211_ATTR_IFINDEX, netdev->ifindex) ||
+		    nla_put_u64(msg, NL80211_ATTR_WDEV, wdev_id(wdev)))
+			goto nla_put_failure;
+	}
+
+	if (nla_put_u32(msg, NL80211_ATTR_RADAR_EVENT, event))
+		goto nla_put_failure;
+
+	if (nl80211_send_chandef(msg, chandef))
+		goto nla_put_failure;
+
+	if (genlmsg_end(msg, hdr) < 0) {
+		nlmsg_free(msg);
+		return;
+	}
+
+	genlmsg_multicast_netns(wiphy_net(&rdev->wiphy), msg, 0,
+				nl80211_mlme_mcgrp.id, gfp);
+	return;
+
+ nla_put_failure:
+	genlmsg_cancel(msg, hdr);
+	nlmsg_free(msg);
+}
+
+void
 nl80211_send_cqm_pktloss_notify(struct cfg80211_registered_device *rdev,
 				struct net_device *netdev, const u8 *peer,
 				u32 num_packets, gfp_t gfp)