wifi: mac80211: handle ieee80211_radar_detected() for MLO

Currently DFS works under assumption there could be only one channel
context in the hardware. Hence, drivers just calls the function
ieee80211_radar_detected() passing the hardware structure. However, with
MLO, this obviously will not work since number of channel contexts will be
more than one and hence drivers would need to pass the channel information
as well on which the radar is detected.

Also, when radar is detected in one of the links, other link's CAC should
not be cancelled.

Hence, in order to support DFS with MLO, do the following changes -
* Add channel context conf pointer as an argument to the function
ieee80211_radar_detected(). During MLO, drivers would have to pass on
which channel context conf radar is detected. Otherwise, drivers could
just pass NULL.
* ieee80211_radar_detected() will iterate over all channel contexts
present and
* if channel context conf is passed, only mark that as radar
detected
* if NULL is passed, then mark all channel contexts as radar
detected
* Then as usual, schedule the radar detected work.
* In the worker, go over all the contexts again and for all such context
which is marked with radar detected, cancel the ongoing CAC by calling
ieee80211_dfs_cac_cancel() and then notify cfg80211 via
cfg80211_radar_event().
* To cancel the CAC, pass the channel context as well where radar is
detected to ieee80211_dfs_cac_cancel(). This ensures that CAC is
canceled only on the links using the provided context, leaving other
links unaffected.

This would also help in scenarios where there is split phy 5 GHz radio,
which is capable of DFS channels in both lower and upper band. In this
case, simultaneous radars can be detected.

Signed-off-by: Aditya Kumar Singh <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Johannes Berg <[e-mail]>

drivers/net/wireless/ath/ath10k/debug.c

···
  * Copyright (c) 2005-2011 Atheros Communications Inc.
  * Copyright (c) 2011-2017 Qualcomm Atheros, Inc.
  * Copyright (c) 2018, The Linux Foundation. All rights reserved.
- * Copyright (c) 2022 Qualcomm Innovation Center, Inc. All rights reserved.
+ * Copyright (c) 2022, 2024 Qualcomm Innovation Center, Inc. All rights reserved.
  */
 
 #include <linux/module.h>
···
 	if (!arvif->is_started)
 		return -EINVAL;
 
-	ieee80211_radar_detected(ar->hw);
+	ieee80211_radar_detected(ar->hw, NULL);
 
 	return count;
 }

drivers/net/wireless/ath/ath10k/mac.c

···
 		 * by indicating that radar was detected.
 		 */
 		ath10k_warn(ar, "failed to start CAC: %d\n", ret);
-		ieee80211_radar_detected(ar->hw);
+		ieee80211_radar_detected(ar->hw, NULL);
 	}
 }
 

drivers/net/wireless/ath/ath10k/wmi.c

···
 	if (ar->dfs_block_radar_events)
 		ath10k_info(ar, "DFS Radar detected, but ignored as requested\n");
 	else
-		ieee80211_radar_detected(ar->hw);
+		ieee80211_radar_detected(ar->hw, NULL);
 }
 
 static void ath10k_radar_confirmation_work(struct work_struct *work)

drivers/net/wireless/ath/ath11k/wmi.c

···
 	if (ar->dfs_block_radar_events)
 		ath11k_info(ab, "DFS Radar detected, but ignored as requested\n");
 	else
-		ieee80211_radar_detected(ar->hw);
+		ieee80211_radar_detected(ar->hw, NULL);
 
 exit:
 	rcu_read_unlock();

drivers/net/wireless/ath/ath12k/wmi.c

···
 	if (ar->dfs_block_radar_events)
 		ath12k_info(ab, "DFS Radar detected, but ignored as requested\n");
 	else
-		ieee80211_radar_detected(ath12k_ar_to_hw(ar));
+		ieee80211_radar_detected(ath12k_ar_to_hw(ar), NULL);
 
 exit:
 	rcu_read_unlock();

drivers/net/wireless/ath/ath9k/dfs.c

···
 	if (!pd->add_pulse(pd, pe, NULL))
 		return;
 	DFS_STAT_INC(sc, radar_detected);
-	ieee80211_radar_detected(sc->hw);
+	ieee80211_radar_detected(sc->hw, NULL);
 }
 
 /*

drivers/net/wireless/ath/ath9k/dfs_debug.c

···
 {
 	struct ath_softc *sc = file->private_data;
 
-	ieee80211_radar_detected(sc->hw);
+	ieee80211_radar_detected(sc->hw, NULL);
 
 	return count;
 }

drivers/net/wireless/mediatek/mt76/mt7615/mcu.c

···
 	if (mt76_phy_dfs_state(mphy) < MT_DFS_STATE_CAC)
 		return;
 
-	ieee80211_radar_detected(mphy->hw);
+	ieee80211_radar_detected(mphy->hw, NULL);
 	dev->hw_pattern++;
 }
 

drivers/net/wireless/mediatek/mt76/mt76x02_dfs.c

···
 		radar_detected = mt76x02_dfs_check_detection(dev);
 		if (radar_detected) {
 			/* sw detector rx radar pattern */
-			ieee80211_radar_detected(dev->mt76.hw);
+			ieee80211_radar_detected(dev->mt76.hw, NULL);
 			mt76x02_dfs_detector_reset(dev);
 
 			return;
···
 
 		/* hw detector rx radar pattern */
 		dfs_pd->stats[i].hw_pattern++;
-		ieee80211_radar_detected(dev->mt76.hw);
+		ieee80211_radar_detected(dev->mt76.hw, NULL);
 		mt76x02_dfs_detector_reset(dev);
 
 		return;

drivers/net/wireless/mediatek/mt76/mt7915/mcu.c

···
 						&dev->rdd2_chandef,
 						GFP_ATOMIC);
 	else
-		ieee80211_radar_detected(mphy->hw);
+		ieee80211_radar_detected(mphy->hw, NULL);
 	dev->hw_pattern++;
 }
 

drivers/net/wireless/mediatek/mt76/mt7996/mcu.c

···
 						&dev->rdd2_chandef,
 						GFP_ATOMIC);
 	else
-		ieee80211_radar_detected(mphy->hw);
+		ieee80211_radar_detected(mphy->hw, NULL);
 	dev->hw_pattern++;
 }
 

drivers/net/wireless/ti/wl18xx/event.c

···
 			    wl18xx_radar_type_decode(mbox->radar_type));
 
 		if (!wl->radar_debug_mode)
-			ieee80211_radar_detected(wl->hw);
+			ieee80211_radar_detected(wl->hw, NULL);
 	}
 
 	if (vector & PERIODIC_SCAN_REPORT_EVENT_ID) {

drivers/net/wireless/virtual/mac80211_hwsim.c

···
 {
 	struct mac80211_hwsim_data *data = dat;
 
-	ieee80211_radar_detected(data->hw);
+	ieee80211_radar_detected(data->hw, NULL);
 
 	return 0;
 }

include/net/mac80211.h

···
  * ieee80211_radar_detected - inform that a radar was detected
  *
  * @hw: pointer as obtained from ieee80211_alloc_hw()
+ * @chanctx_conf: Channel context on which radar is detected. Mandatory to
+ *	pass a valid pointer during MLO. For non-MLO %NULL can be passed
  */
-void ieee80211_radar_detected(struct ieee80211_hw *hw);
+void ieee80211_radar_detected(struct ieee80211_hw *hw,
+			      struct ieee80211_chanctx_conf *chanctx_conf);
 
 /**
  * ieee80211_chswitch_done - Complete channel switch process

net/mac80211/chan.c

···
 	ctx->mode = mode;
 	ctx->conf.radar_enabled = false;
 	ctx->conf.radio_idx = radio_idx;
+	ctx->radar_detected = false;
 	_ieee80211_recalc_chanctx_min_def(local, ctx, NULL, false);
 
 	return ctx;

net/mac80211/ieee80211_i.h

···
 	struct ieee80211_chan_req req;
 
 	struct ieee80211_chanctx_conf conf;
+
+	bool radar_detected;
 };
 
 struct mac80211_qos_map {
···
 bool ieee80211_is_radar_required(struct ieee80211_local *local);
 
 void ieee80211_dfs_cac_timer_work(struct wiphy *wiphy, struct wiphy_work *work);
-void ieee80211_dfs_cac_cancel(struct ieee80211_local *local);
+void ieee80211_dfs_cac_cancel(struct ieee80211_local *local,
+			      struct ieee80211_chanctx *chanctx);
 void ieee80211_dfs_radar_detected_work(struct wiphy *wiphy,
 				       struct wiphy_work *work);
 int ieee80211_send_action_csa(struct ieee80211_sub_if_data *sdata,

net/mac80211/pm.c

···
 
 	ieee80211_scan_cancel(local);
 
-	ieee80211_dfs_cac_cancel(local);
+	ieee80211_dfs_cac_cancel(local, NULL);
 
 	ieee80211_roc_purge(local, NULL);
 

net/mac80211/util.c

···
 	return ts;
 }
 
-void ieee80211_dfs_cac_cancel(struct ieee80211_local *local)
+/* Cancel CAC for the interfaces under the specified @local. If @ctx is
+ * also provided, only the interfaces using that ctx will be canceled.
+ */
+void ieee80211_dfs_cac_cancel(struct ieee80211_local *local,
+			      struct ieee80211_chanctx *ctx)
 {
 	struct ieee80211_sub_if_data *sdata;
 	struct cfg80211_chan_def chandef;
 	struct ieee80211_link_data *link;
+	struct ieee80211_chanctx_conf *chanctx_conf;
 	unsigned int link_id;
 
 	lockdep_assert_wiphy(local->hw.wiphy);
···
 			link = sdata_dereference(sdata->link[link_id],
 						 sdata);
 			if (!link)
+				continue;
+
+			chanctx_conf = sdata_dereference(link->conf->chanctx_conf,
+							 sdata);
+			if (ctx && &ctx->conf != chanctx_conf)
 				continue;
 
 			wiphy_delayed_work_cancel(local->hw.wiphy,
···
 {
 	struct ieee80211_local *local =
 		container_of(work, struct ieee80211_local, radar_detected_work);
-	struct cfg80211_chan_def chandef = local->hw.conf.chandef;
+	struct cfg80211_chan_def chandef;
 	struct ieee80211_chanctx *ctx;
-	int num_chanctx = 0;
 
 	lockdep_assert_wiphy(local->hw.wiphy);
 
···
 		if (ctx->replace_state == IEEE80211_CHANCTX_REPLACES_OTHER)
 			continue;
 
-		num_chanctx++;
+		if (!ctx->radar_detected)
+			continue;
+
+		ctx->radar_detected = false;
+
 		chandef = ctx->conf.def;
-	}
 
-	ieee80211_dfs_cac_cancel(local);
-
-	if (num_chanctx > 1)
-		/* XXX: multi-channel is not supported yet */
-		WARN_ON(1);
-	else
+		ieee80211_dfs_cac_cancel(local, ctx);
 		cfg80211_radar_event(local->hw.wiphy, &chandef, GFP_KERNEL);
+	}
 }
 
-void ieee80211_radar_detected(struct ieee80211_hw *hw)
+static void
+ieee80211_radar_mark_chan_ctx_iterator(struct ieee80211_hw *hw,
+				       struct ieee80211_chanctx_conf *chanctx_conf,
+				       void *data)
+{
+	struct ieee80211_chanctx *ctx =
+		container_of(chanctx_conf, struct ieee80211_chanctx,
+			     conf);
+
+	if (ctx->replace_state == IEEE80211_CHANCTX_REPLACES_OTHER)
+		return;
+
+	if (data && data != chanctx_conf)
+		return;
+
+	ctx->radar_detected = true;
+}
+
+void ieee80211_radar_detected(struct ieee80211_hw *hw,
+			      struct ieee80211_chanctx_conf *chanctx_conf)
 {
 	struct ieee80211_local *local = hw_to_local(hw);
 
 	trace_api_radar_detected(local);
+
+	ieee80211_iter_chan_contexts_atomic(hw, ieee80211_radar_mark_chan_ctx_iterator,
+					    chanctx_conf);
 
 	wiphy_work_queue(hw->wiphy, &local->radar_detected_work);
 }