wifi: ath12k: modify remain on channel for single wiphy

When multiple radios are advertised as a single wiphy which supports various
bands, vdev creation for the vif is deferred until channel is assigned to it.
If a remain on channel (RoC) request is received from mac80211, select the
corresponding radio (ar) based on channel and create a vdev on that radio to
initiate an RoC scan.

Note that on RoC completion this vdev is not deleted. If a new RoC/hw scan
request is seen on that same vif for a different band the vdev will be deleted
and created on the new radio supporting the request.

Also if the RoC scan is requested when the vdev is in started state, no
switching to new radio is allowed and RoC request can be accepted only on
channels within same radio.

Tested-on: QCN9274 hw2.0 PCI WLAN.WBE.1.0.1-00029-QCAHKSWPL_SILICONZ-1
Tested-on: WCN7850 hw2.0 PCI WLAN.HMT.1.0.c5-00481-QCAHMTSWPL_V1.0_V2.0_SILICONZ-3
Signed-off-by: Rameshkumar Sundaram <quic_ramess@quicinc.com>
Acked-by: Jeff Johnson <quic_jjohnson@quicinc.com>
Signed-off-by: Kalle Valo <quic_kvalo@quicinc.com>
Link: https://msgid.link/20240528082739.1226758-1-quic_ramess@quicinc.com

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

@@ -3372,7 +3372,7 @@ static void ath12k_mac_op_bss_info_changed(struct ieee80211_hw *hw,
 static struct ath12k*
 ath12k_mac_select_scan_device(struct ieee80211_hw *hw,
 			      struct ieee80211_vif *vif,
-			      struct ieee80211_scan_request *req)
+			      u32 center_freq)
 {
 	struct ath12k_hw *ah = hw->priv;
 	enum nl80211_band band;
@@ -3389,9 +3389,9 @@ ath12k_mac_select_scan_device(struct ieee80211_hw *hw,
 	 * split the hw request and perform multiple scans
 	 */
 
-	if (req->req.channels[0]->center_freq < ATH12K_MIN_5G_FREQ)
+	if (center_freq < ATH12K_MIN_5G_FREQ)
 		band = NL80211_BAND_2GHZ;
-	else if (req->req.channels[0]->center_freq < ATH12K_MIN_6G_FREQ)
+	else if (center_freq < ATH12K_MIN_6G_FREQ)
 		band = NL80211_BAND_5GHZ;
 	else
 		band = NL80211_BAND_6GHZ;
@@ -3591,7 +3591,7 @@ static int ath12k_mac_op_hw_scan(struct ieee80211_hw *hw,
 	/* Since the targeted scan device could depend on the frequency
 	 * requested in the hw_req, select the corresponding radio
 	 */
-	ar = ath12k_mac_select_scan_device(hw, vif, hw_req);
+	ar = ath12k_mac_select_scan_device(hw, vif, hw_req->req.channels[0]->center_freq);
 	if (!ar)
 		return -EINVAL;
 
@@ -8416,12 +8416,68 @@ static int ath12k_mac_op_remain_on_channel(struct ieee80211_hw *hw,
 	struct ath12k_vif *arvif = ath12k_vif_to_arvif(vif);
 	struct ath12k_hw *ah = ath12k_hw_to_ah(hw);
 	struct ath12k_wmi_scan_req_arg arg;
-	struct ath12k *ar;
+	struct ath12k *ar, *prev_ar;
 	u32 scan_time_msec;
+	bool create = true;
 	int ret;
 
-	ar = ath12k_ah_to_ar(ah, 0);
+	if (ah->num_radio == 1) {
+		WARN_ON(!arvif->is_created);
+		ar = ath12k_ah_to_ar(ah, 0);
+		goto scan;
+	}
+
+	ar = ath12k_mac_select_scan_device(hw, vif, chan->center_freq);
+	if (!ar)
+		return -EINVAL;
+
+	/* If the vif is already assigned to a specific vdev of an ar,
+	 * check whether its already started, vdev which is started
+	 * are not allowed to switch to a new radio.
+	 * If the vdev is not started, but was earlier created on a
+	 * different ar, delete that vdev and create a new one. We don't
+	 * delete at the scan stop as an optimization to avoid redundant
+	 * delete-create vdev's for the same ar, in case the request is
+	 * always on the same band for the vif
+	 */
+	if (arvif->is_created) {
+		if (WARN_ON(!arvif->ar))
+			return -EINVAL;
+
+		if (ar != arvif->ar && arvif->is_started)
+			return -EBUSY;
+
+		if (ar != arvif->ar) {
+			/* backup the previously used ar ptr, since the vdev delete
+			 * would assign the arvif->ar to NULL after the call
+			 */
+			prev_ar = arvif->ar;
+			mutex_lock(&prev_ar->conf_mutex);
+			ret = ath12k_mac_vdev_delete(prev_ar, vif);
+			mutex_unlock(&prev_ar->conf_mutex);
+			if (ret) {
+				ath12k_warn(prev_ar->ab,
+					    "unable to delete scan vdev for roc: %d\n",
+					    ret);
+				return ret;
+			}
+		} else {
+			create = false;
+		}
+	}
+
+	if (create) {
+		mutex_lock(&ar->conf_mutex);
+		ret = ath12k_mac_vdev_create(ar, vif);
+		mutex_unlock(&ar->conf_mutex);
+		if (ret) {
+			ath12k_warn(ar->ab, "unable to create scan vdev for roc: %d\n",
+				    ret);
+			return -EINVAL;
+		}
+	}
 
+scan:
 	mutex_lock(&ar->conf_mutex);
 	spin_lock_bh(&ar->data_lock);