wifi: wfx: allow to send frames during ROC

Until now, all the traffic was blocked during scan operation. However,
scan operation is going to be used to implement Remain On Channel (ROC).
In this case, special frames (marked with IEEE80211_TX_CTL_TX_OFFCHAN)
must be sent during the operation.

These frames need to be sent on the virtual interface #2. Until now,
this interface was only used by the device for internal purpose. But
since API 3.9, it can be used to send data during scan operation (we
hijack the scan process to implement ROC).

Thus, we need to change a bit the way we match the frames with the
interface.

Fortunately, the frames received during the scan are marked with the
correct interface number. So there is no change to do on this part.

Signed-off-by: Jérôme Pouiller <[e-mail]>
Signed-off-by: Kalle Valo <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]

drivers/net/wireless/silabs/wfx/data_tx.c

···
 	return req;
 }
 
+struct wfx_vif *wfx_skb_wvif(struct wfx_dev *wdev, struct sk_buff *skb)
+{
+	struct wfx_tx_priv *tx_priv = wfx_skb_tx_priv(skb);
+	struct wfx_hif_msg *hif = (struct wfx_hif_msg *)skb->data;
+
+	if (tx_priv->vif_id != hif->interface && hif->interface != 2) {
+		dev_err(wdev->dev, "corrupted skb");
+		return wdev_to_wvif(wdev, hif->interface);
+	}
+	return wdev_to_wvif(wdev, tx_priv->vif_id);
+}
+
 static u8 wfx_tx_get_link_id(struct wfx_vif *wvif, struct ieee80211_sta *sta,
 			     struct ieee80211_hdr *hdr)
 {
···
 	/* Fill tx_priv */
 	tx_priv = (struct wfx_tx_priv *)tx_info->rate_driver_data;
 	tx_priv->icv_size = wfx_tx_get_icv_len(hw_key);
+	tx_priv->vif_id = wvif->id;
 
 	/* Fill hif_msg */
 	WARN(skb_headroom(skb) < wmsg_len, "not enough space in skb");
···
 	hif_msg = (struct wfx_hif_msg *)skb->data;
 	hif_msg->len = cpu_to_le16(skb->len);
 	hif_msg->id = HIF_REQ_ID_TX;
-	hif_msg->interface = wvif->id;
+	if (tx_info->flags & IEEE80211_TX_CTL_TX_OFFCHAN)
+		hif_msg->interface = 2;
+	else
+		hif_msg->interface = wvif->id;
 	if (skb->len > le16_to_cpu(wvif->wdev->hw_caps.size_inp_ch_buf)) {
 		dev_warn(wvif->wdev->dev,
 			 "requested frame size (%d) is larger than maximum supported (%d)\n",
···
 	req->fc_offset = offset;
 	/* Queue index are inverted between firmware and Linux */
 	req->queue_id = 3 - queue_id;
-	req->peer_sta_id = wfx_tx_get_link_id(wvif, sta, hdr);
-	req->retry_policy_index = wfx_tx_get_retry_policy_id(wvif, tx_info);
-	req->frame_format = wfx_tx_get_frame_format(tx_info);
+	if (tx_info->flags & IEEE80211_TX_CTL_TX_OFFCHAN) {
+		req->peer_sta_id = HIF_LINK_ID_NOT_ASSOCIATED;
+		req->retry_policy_index = HIF_TX_RETRY_POLICY_INVALID;
+		req->frame_format = HIF_FRAME_FORMAT_NON_HT;
+	} else {
+		req->peer_sta_id = wfx_tx_get_link_id(wvif, sta, hdr);
+		req->retry_policy_index = wfx_tx_get_retry_policy_id(wvif, tx_info);
+		req->frame_format = wfx_tx_get_frame_format(tx_info);
+	}
 	if (tx_info->driver_rates[0].flags & IEEE80211_TX_RC_SHORT_GI)
 		req->short_gi = 1;
 	if (tx_info->flags & IEEE80211_TX_CTL_SEND_AFTER_DTIM)
···
 	}
 	tx_info = IEEE80211_SKB_CB(skb);
 	tx_priv = wfx_skb_tx_priv(skb);
-	wvif = wdev_to_wvif(wdev, ((struct wfx_hif_msg *)skb->data)->interface);
+	wvif = wfx_skb_wvif(wdev, skb);
 	WARN_ON(!wvif);
 	if (!wvif)
 		return;
···
 	struct wfx_dev *wdev = hw->priv;
 	struct sk_buff_head dropped;
 	struct wfx_vif *wvif;
-	struct wfx_hif_msg *hif;
 	struct sk_buff *skb;
 
 	skb_queue_head_init(&dropped);
···
 	if (wdev->chip_frozen)
 		wfx_pending_drop(wdev, &dropped);
 	while ((skb = skb_dequeue(&dropped)) != NULL) {
-		hif = (struct wfx_hif_msg *)skb->data;
-		wvif = wdev_to_wvif(wdev, hif->interface);
+		wvif = wfx_skb_wvif(wdev, skb);
 		ieee80211_tx_info_clear_status(IEEE80211_SKB_CB(skb));
 		wfx_skb_dtor(wvif, skb);
 	}

drivers/net/wireless/silabs/wfx/data_tx.h

···
 struct wfx_tx_priv {
 	ktime_t xmit_timestamp;
 	unsigned char icv_size;
+	unsigned char vif_id;
 };
 
 void wfx_tx_policy_init(struct wfx_vif *wvif);
···
 
 struct wfx_tx_priv *wfx_skb_tx_priv(struct sk_buff *skb);
 struct wfx_hif_req_tx *wfx_skb_txreq(struct sk_buff *skb);
+struct wfx_vif *wfx_skb_wvif(struct wfx_dev *wdev, struct sk_buff *skb);
 
 #endif

drivers/net/wireless/silabs/wfx/queue.c

···
 	for (i = 0; i < IEEE80211_NUM_ACS; ++i) {
 		skb_queue_head_init(&wvif->tx_queue[i].normal);
 		skb_queue_head_init(&wvif->tx_queue[i].cab);
+		skb_queue_head_init(&wvif->tx_queue[i].offchan);
 		wvif->tx_queue[i].priority = priorities[i];
 	}
 }
 
 bool wfx_tx_queue_empty(struct wfx_vif *wvif, struct wfx_queue *queue)
 {
-	return skb_queue_empty_lockless(&queue->normal) && skb_queue_empty_lockless(&queue->cab);
+	return skb_queue_empty_lockless(&queue->normal) &&
+	       skb_queue_empty_lockless(&queue->cab) &&
+	       skb_queue_empty_lockless(&queue->offchan);
 }
 
 void wfx_tx_queues_check_empty(struct wfx_vif *wvif)
···
 void wfx_tx_queue_drop(struct wfx_vif *wvif, struct wfx_queue *queue,
 		       struct sk_buff_head *dropped)
 {
-	__wfx_tx_queue_drop(wvif, &queue->cab, dropped);
 	__wfx_tx_queue_drop(wvif, &queue->normal, dropped);
+	__wfx_tx_queue_drop(wvif, &queue->cab, dropped);
+	__wfx_tx_queue_drop(wvif, &queue->offchan, dropped);
 	wake_up(&wvif->wdev->tx_dequeue);
 }
 
···
 	struct wfx_queue *queue = &wvif->tx_queue[skb_get_queue_mapping(skb)];
 	struct ieee80211_tx_info *tx_info = IEEE80211_SKB_CB(skb);
 
-	if (tx_info->flags & IEEE80211_TX_CTL_SEND_AFTER_DTIM)
+	if (tx_info->flags & IEEE80211_TX_CTL_TX_OFFCHAN)
+		skb_queue_tail(&queue->offchan, skb);
+	else if (tx_info->flags & IEEE80211_TX_CTL_SEND_AFTER_DTIM)
 		skb_queue_tail(&queue->cab, skb);
 	else
 		skb_queue_tail(&queue->normal, skb);
···
 {
 	struct wfx_queue *queue;
 	struct wfx_vif *wvif;
-	struct wfx_hif_msg *hif;
 	struct sk_buff *skb;
 
 	WARN(!wdev->chip_frozen, "%s should only be used to recover a frozen device", __func__);
 	while ((skb = skb_dequeue(&wdev->tx_pending)) != NULL) {
-		hif = (struct wfx_hif_msg *)skb->data;
-		wvif = wdev_to_wvif(wdev, hif->interface);
+		wvif = wfx_skb_wvif(wdev, skb);
 		if (wvif) {
 			queue = &wvif->tx_queue[skb_get_queue_mapping(skb)];
 			WARN_ON(skb_get_queue_mapping(skb) > 3);
···
 		if (req->packet_id != packet_id)
 			continue;
 		spin_unlock_bh(&wdev->tx_pending.lock);
-		wvif = wdev_to_wvif(wdev, hif->interface);
+		wvif = wfx_skb_wvif(wdev, skb);
 		if (wvif) {
 			queue = &wvif->tx_queue[skb_get_queue_mapping(skb)];
 			WARN_ON(skb_get_queue_mapping(skb) > 3);
···
 			num_queues++;
 		}
 	}
+
+	wvif = NULL;
+	while ((wvif = wvif_iterate(wdev, wvif)) != NULL) {
+		for (i = 0; i < num_queues; i++) {
+			skb = skb_dequeue(&queues[i]->offchan);
+			if (!skb)
+				continue;
+			hif = (struct wfx_hif_msg *)skb->data;
+			/* Offchan frames are assigned to a special interface.
+			 * The only interface allowed to send data during scan.
+			 */
+			WARN_ON(hif->interface != 2);
+			atomic_inc(&queues[i]->pending_frames);
+			trace_queues_stats(wdev, queues[i]);
+			return skb;
+		}
+	}
+
+	if (mutex_is_locked(&wdev->scan_lock))
+		return NULL;
 
 	wvif = NULL;
 	while ((wvif = wvif_iterate(wdev, wvif)) != NULL) {

drivers/net/wireless/silabs/wfx/queue.h

···
 struct wfx_queue {
 	struct sk_buff_head normal;
 	struct sk_buff_head cab; /* Content After (DTIM) Beacon */
+	struct sk_buff_head offchan;
 	atomic_t            pending_frames;
 	int                 priority;
 };