mac80211: add radar detection command/event

Add command to trigger radar detection in the driver/FW.
Once radar detection is started it should continuously
monitor for radars as long as the channel active.
If radar is detected usermode notified with 'radar
detected' event.

Scanning and remain on channel functionality must be disabled
while doing radar detection/scanning, and vice versa.

Based on original patch by Victor Goldenshtein <victorg@ti.com>

Signed-off-by: Simon Wunderlich <siwu@hrz.tu-chemnitz.de>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
diff --git a/include/net/mac80211.h b/include/net/mac80211.h
index 0eaa909..7241962 100644
--- a/include/net/mac80211.h
+++ b/include/net/mac80211.h
@@ -147,10 +147,12 @@
  * enum ieee80211_chanctx_change - change flag for channel context
  * @IEEE80211_CHANCTX_CHANGE_WIDTH: The channel width changed
  * @IEEE80211_CHANCTX_CHANGE_RX_CHAINS: The number of RX chains changed
+ * @IEEE80211_CHANCTX_CHANGE_RADAR: radar detection flag changed
  */
 enum ieee80211_chanctx_change {
 	IEEE80211_CHANCTX_CHANGE_WIDTH		= BIT(0),
 	IEEE80211_CHANCTX_CHANGE_RX_CHAINS	= BIT(1),
+	IEEE80211_CHANCTX_CHANGE_RADAR		= BIT(2),
 };
 
 /**
@@ -165,6 +167,7 @@
  * @rx_chains_dynamic: The number of RX chains that must be enabled
  *	after RTS/CTS handshake to receive SMPS MIMO transmissions;
  *	this will always be >= @rx_chains_static.
+ * @radar_enabled: whether radar detection is enabled on this channel.
  * @drv_priv: data area for driver use, will always be aligned to
  *	sizeof(void *), size is determined in hw information.
  */
@@ -173,6 +176,8 @@
 
 	u8 rx_chains_static, rx_chains_dynamic;
 
+	bool radar_enabled;
+
 	u8 drv_priv[0] __aligned(sizeof(void *));
 };
 
@@ -967,6 +972,7 @@
  *
  * @channel: the channel to tune to
  * @channel_type: the channel (HT) type
+ * @radar_enabled: whether radar detection is enabled
  *
  * @long_frame_max_tx_count: Maximum number of transmissions for a "long" frame
  *    (a frame not RTS protected), called "dot11LongRetryLimit" in 802.11,
@@ -993,6 +999,7 @@
 
 	struct ieee80211_channel *channel;
 	enum nl80211_channel_type channel_type;
+	bool radar_enabled;
 	enum ieee80211_smps_mode smps_mode;
 };
 
@@ -3945,6 +3952,13 @@
 			       gfp_t gfp);
 
 /**
+ * ieee80211_radar_detected - inform that a radar was detected
+ *
+ * @hw: pointer as obtained from ieee80211_alloc_hw()
+ */
+void ieee80211_radar_detected(struct ieee80211_hw *hw);
+
+/**
  * ieee80211_chswitch_done - Complete channel switch process
  * @vif: &struct ieee80211_vif pointer from the add_interface callback.
  * @success: make the channel switch successful or not
diff --git a/net/mac80211/cfg.c b/net/mac80211/cfg.c
index e3dec80..0969978 100644
--- a/net/mac80211/cfg.c
+++ b/net/mac80211/cfg.c
@@ -928,6 +928,7 @@
 	/* TODO: make hostapd tell us what it wants */
 	sdata->smps_mode = IEEE80211_SMPS_OFF;
 	sdata->needed_rx_chains = sdata->local->rx_chains;
+	sdata->radar_required = params->radar_required;
 
 	err = ieee80211_vif_use_channel(sdata, &params->chandef,
 					IEEE80211_CHANCTX_SHARED);
@@ -2395,7 +2396,8 @@
 	INIT_LIST_HEAD(&roc->dependents);
 
 	/* if there's one pending or we're scanning, queue this one */
-	if (!list_empty(&local->roc_list) || local->scanning)
+	if (!list_empty(&local->roc_list) ||
+	    local->scanning || local->radar_detect_enabled)
 		goto out_check_combine;
 
 	/* if not HW assist, just queue & schedule work */
@@ -2645,6 +2647,37 @@
 	return ieee80211_cancel_roc(local, cookie, false);
 }
 
+static int ieee80211_start_radar_detection(struct wiphy *wiphy,
+					   struct net_device *dev,
+					   struct cfg80211_chan_def *chandef)
+{
+	struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
+	struct ieee80211_local *local = sdata->local;
+	unsigned long timeout;
+	int err;
+
+	if (!list_empty(&local->roc_list) || local->scanning)
+		return -EBUSY;
+
+	/* whatever, but channel contexts should not complain about that one */
+	sdata->smps_mode = IEEE80211_SMPS_OFF;
+	sdata->needed_rx_chains = local->rx_chains;
+	sdata->radar_required = true;
+
+	mutex_lock(&local->iflist_mtx);
+	err = ieee80211_vif_use_channel(sdata, chandef,
+					IEEE80211_CHANCTX_SHARED);
+	mutex_unlock(&local->iflist_mtx);
+	if (err)
+		return err;
+
+	timeout = msecs_to_jiffies(IEEE80211_DFS_MIN_CAC_TIME_MS);
+	ieee80211_queue_delayed_work(&sdata->local->hw,
+				     &sdata->dfs_cac_timer_work, timeout);
+
+	return 0;
+}
+
 static int ieee80211_mgmt_tx(struct wiphy *wiphy, struct wireless_dev *wdev,
 			     struct ieee80211_channel *chan, bool offchan,
 			     unsigned int wait, const u8 *buf, size_t len,
@@ -3350,4 +3383,5 @@
 	.get_et_stats = ieee80211_get_et_stats,
 	.get_et_strings = ieee80211_get_et_strings,
 	.get_channel = ieee80211_cfg_get_channel,
+	.start_radar_detection = ieee80211_start_radar_detection,
 };
diff --git a/net/mac80211/chan.c b/net/mac80211/chan.c
index 038f249..2e6faed 100644
--- a/net/mac80211/chan.c
+++ b/net/mac80211/chan.c
@@ -193,6 +193,7 @@
 	if (ctx->refcount > 0) {
 		ieee80211_recalc_chanctx_chantype(sdata->local, ctx);
 		ieee80211_recalc_smps_chanctx(local, ctx);
+		ieee80211_recalc_radar_chanctx(local, ctx);
 	}
 }
 
@@ -216,6 +217,37 @@
 		ieee80211_free_chanctx(local, ctx);
 }
 
+void ieee80211_recalc_radar_chanctx(struct ieee80211_local *local,
+				    struct ieee80211_chanctx *chanctx)
+{
+	struct ieee80211_sub_if_data *sdata;
+	bool radar_enabled = false;
+
+	lockdep_assert_held(&local->chanctx_mtx);
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(sdata, &local->interfaces, list) {
+		if (sdata->radar_required) {
+			radar_enabled = true;
+			break;
+		}
+	}
+	rcu_read_unlock();
+
+	if (radar_enabled == chanctx->conf.radar_enabled)
+		return;
+
+	chanctx->conf.radar_enabled = radar_enabled;
+	local->radar_detect_enabled = chanctx->conf.radar_enabled;
+
+	if (!local->use_chanctx) {
+		local->hw.conf.radar_enabled = chanctx->conf.radar_enabled;
+		ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
+	}
+
+	drv_change_chanctx(local, chanctx, IEEE80211_CHANCTX_CHANGE_RADAR);
+}
+
 void ieee80211_recalc_smps_chanctx(struct ieee80211_local *local,
 				   struct ieee80211_chanctx *chanctx)
 {
@@ -331,6 +363,7 @@
 	}
 
 	ieee80211_recalc_smps_chanctx(local, ctx);
+	ieee80211_recalc_radar_chanctx(local, ctx);
  out:
 	mutex_unlock(&local->chanctx_mtx);
 	return ret;
diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index 76cdcfc..0e0a977 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -722,6 +722,9 @@
 	int user_power_level; /* in dBm */
 	int ap_power_level; /* in dBm */
 
+	bool radar_required;
+	struct delayed_work dfs_cac_timer_work;
+
 	/*
 	 * AP this belongs to: self in AP mode and
 	 * corresponding AP in VLAN mode, NULL for
@@ -942,6 +945,10 @@
 	/* wowlan is enabled -- don't reconfig on resume */
 	bool wowlan;
 
+	/* DFS/radar detection is enabled */
+	bool radar_detect_enabled;
+	struct work_struct radar_detected_work;
+
 	/* number of RX chains the hardware has */
 	u8 rx_chains;
 
@@ -1606,6 +1613,13 @@
 
 void ieee80211_recalc_smps_chanctx(struct ieee80211_local *local,
 				   struct ieee80211_chanctx *chanctx);
+void ieee80211_recalc_radar_chanctx(struct ieee80211_local *local,
+				    struct ieee80211_chanctx *chanctx);
+
+void ieee80211_dfs_cac_timer(unsigned long data);
+void ieee80211_dfs_cac_timer_work(struct work_struct *work);
+void ieee80211_dfs_cac_cancel(struct ieee80211_local *local);
+void ieee80211_dfs_radar_detected_work(struct work_struct *work);
 
 #ifdef CONFIG_MAC80211_NOINLINE
 #define debug_noinline noinline
diff --git a/net/mac80211/iface.c b/net/mac80211/iface.c
index 40ff030..e9223ce 100644
--- a/net/mac80211/iface.c
+++ b/net/mac80211/iface.c
@@ -749,6 +749,16 @@
 
 	cancel_work_sync(&sdata->recalc_smps);
 
+	cancel_delayed_work_sync(&sdata->dfs_cac_timer_work);
+
+	if (sdata->wdev.cac_started) {
+		mutex_lock(&local->iflist_mtx);
+		ieee80211_vif_release_channel(sdata);
+		mutex_unlock(&local->iflist_mtx);
+		cfg80211_cac_event(sdata->dev, NL80211_RADAR_CAC_ABORTED,
+				   GFP_KERNEL);
+	}
+
 	/* APs need special treatment */
 	if (sdata->vif.type == NL80211_IFTYPE_AP) {
 		struct ieee80211_sub_if_data *vlan, *tmpsdata;
@@ -1513,6 +1523,8 @@
 	spin_lock_init(&sdata->cleanup_stations_lock);
 	INIT_LIST_HEAD(&sdata->cleanup_stations);
 	INIT_WORK(&sdata->cleanup_stations_wk, ieee80211_cleanup_sdata_stas_wk);
+	INIT_DELAYED_WORK(&sdata->dfs_cac_timer_work,
+			  ieee80211_dfs_cac_timer_work);
 
 	for (i = 0; i < IEEE80211_NUM_BANDS; i++) {
 		struct ieee80211_supported_band *sband;
diff --git a/net/mac80211/main.c b/net/mac80211/main.c
index 38b3468..9cdbc77 100644
--- a/net/mac80211/main.c
+++ b/net/mac80211/main.c
@@ -621,6 +621,9 @@
 
 	INIT_WORK(&local->restart_work, ieee80211_restart_work);
 
+	INIT_WORK(&local->radar_detected_work,
+		  ieee80211_dfs_radar_detected_work);
+
 	INIT_WORK(&local->reconfig_filter, ieee80211_reconfig_filter);
 	local->smps_mode = IEEE80211_SMPS_OFF;
 
@@ -713,6 +716,16 @@
 		 */
 		if (local->hw.wiphy->interface_modes & BIT(NL80211_IFTYPE_WDS))
 			return -EINVAL;
+
+		/* DFS currently not supported with channel context drivers */
+		for (i = 0; i < local->hw.wiphy->n_iface_combinations; i++) {
+			const struct ieee80211_iface_combination *comb;
+
+			comb = &local->hw.wiphy->iface_combinations[i];
+
+			if (comb->radar_detect_widths)
+				return -EINVAL;
+		}
 	}
 
 	/* Only HW csum features are currently compatible with mac80211 */
diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c
index efb2276..7d4cde7 100644
--- a/net/mac80211/mlme.c
+++ b/net/mac80211/mlme.c
@@ -1212,6 +1212,19 @@
 	ieee80211_queue_work(&local->hw, &local->dynamic_ps_enable_work);
 }
 
+void ieee80211_dfs_cac_timer_work(struct work_struct *work)
+{
+	struct delayed_work *delayed_work =
+		container_of(work, struct delayed_work, work);
+	struct ieee80211_sub_if_data *sdata =
+		container_of(delayed_work, struct ieee80211_sub_if_data,
+			     dfs_cac_timer_work);
+
+	ieee80211_vif_release_channel(sdata);
+
+	cfg80211_cac_event(sdata->dev, NL80211_RADAR_CAC_FINISHED, GFP_KERNEL);
+}
+
 /* MLME */
 static bool ieee80211_sta_wmm_params(struct ieee80211_local *local,
 				     struct ieee80211_sub_if_data *sdata,
diff --git a/net/mac80211/pm.c b/net/mac80211/pm.c
index 53801d2..d0275f3 100644
--- a/net/mac80211/pm.c
+++ b/net/mac80211/pm.c
@@ -38,6 +38,8 @@
 
 	ieee80211_scan_cancel(local);
 
+	ieee80211_dfs_cac_cancel(local);
+
 	if (hw->flags & IEEE80211_HW_AMPDU_AGGREGATION) {
 		mutex_lock(&local->sta_mtx);
 		list_for_each_entry(sta, &local->sta_list, list) {
diff --git a/net/mac80211/scan.c b/net/mac80211/scan.c
index 6d0b89e..43a45cf 100644
--- a/net/mac80211/scan.c
+++ b/net/mac80211/scan.c
@@ -351,6 +351,9 @@
 static bool ieee80211_can_scan(struct ieee80211_local *local,
 			       struct ieee80211_sub_if_data *sdata)
 {
+	if (local->radar_detect_enabled)
+		return false;
+
 	if (!list_empty(&local->roc_list))
 		return false;
 
diff --git a/net/mac80211/trace.h b/net/mac80211/trace.h
index 0bdd7ae..1183c4a 100644
--- a/net/mac80211/trace.h
+++ b/net/mac80211/trace.h
@@ -1862,6 +1862,25 @@
 		  LOCAL_PR_ARG, VIF_PR_ARG, __entry->key_idx)
 );
 
+TRACE_EVENT(api_radar_detected,
+	TP_PROTO(struct ieee80211_local *local),
+
+	TP_ARGS(local),
+
+	TP_STRUCT__entry(
+		LOCAL_ENTRY
+	),
+
+	TP_fast_assign(
+		LOCAL_ASSIGN;
+	),
+
+	TP_printk(
+		LOCAL_PR_FMT " radar detected",
+		LOCAL_PR_ARG
+	)
+);
+
 #ifdef CONFIG_MAC80211_MESSAGE_TRACING
 #undef TRACE_SYSTEM
 #define TRACE_SYSTEM mac80211_msg
diff --git a/net/mac80211/util.c b/net/mac80211/util.c
index 6cb71a3..218cb52 100644
--- a/net/mac80211/util.c
+++ b/net/mac80211/util.c
@@ -2133,3 +2133,49 @@
 
 	return ts;
 }
+
+void ieee80211_dfs_cac_cancel(struct ieee80211_local *local)
+{
+	struct ieee80211_sub_if_data *sdata;
+
+	mutex_lock(&local->iflist_mtx);
+	list_for_each_entry(sdata, &local->interfaces, list) {
+		cancel_delayed_work_sync(&sdata->dfs_cac_timer_work);
+
+		if (sdata->wdev.cac_started) {
+			ieee80211_vif_release_channel(sdata);
+			cfg80211_cac_event(sdata->dev,
+					   NL80211_RADAR_CAC_ABORTED,
+					   GFP_KERNEL);
+		}
+	}
+	mutex_unlock(&local->iflist_mtx);
+}
+
+void ieee80211_dfs_radar_detected_work(struct work_struct *work)
+{
+	struct ieee80211_local *local =
+		container_of(work, struct ieee80211_local, radar_detected_work);
+	struct cfg80211_chan_def chandef;
+
+	ieee80211_dfs_cac_cancel(local);
+
+	if (local->use_chanctx)
+		/* currently not handled */
+		WARN_ON(1);
+	else {
+		cfg80211_chandef_create(&chandef, local->hw.conf.channel,
+					local->hw.conf.channel_type);
+		cfg80211_radar_event(local->hw.wiphy, &chandef, GFP_KERNEL);
+	}
+}
+
+void ieee80211_radar_detected(struct ieee80211_hw *hw)
+{
+	struct ieee80211_local *local = hw_to_local(hw);
+
+	trace_api_radar_detected(local);
+
+	ieee80211_queue_work(hw, &local->radar_detected_work);
+}
+EXPORT_SYMBOL(ieee80211_radar_detected);