rtw88: kick off TX packets once for higher efficiency

Driver used to kick off every TX packets, that will waste some
time while we can do better to kick off the TX packets once after
they are all prepared to be transmitted.

For PCI, it uses DMA engine to transfer the SKBs to the device,
and the transition of the state of the DMA engine could be a cost.
Driver can save some time to kick off multiple SKBs once so that
the DMA engine will have only one transition.

So, split rtw_hci_ops::tx() to rtw_hci_ops::tx_write() and
rtw_hci_ops::tx_kick_off() to explicitly kick the SKBs off after
they are written to the prepared buffer. For packets come from
ieee80211_ops::tx(), write one and then kick it off immediately.
For packets queued in TX queue, which come from
ieee80211_ops::wake_tx_queue(), we can dequeue them, write them
to the buffer, and then kick them off together.

Signed-off-by: Yan-Hsuan Chuang <yhchuang@realtek.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20200312080852.16684-6-yhchuang@realtek.com

1 files changed, 54 insertions, 23 deletions

diff --git a/drivers/net/wireless/realtek/rtw88/tx.c b/drivers/net/wireless/realtek/rtw88/tx.c
index 0447228e66be..b31eb4d9664b 100644
--- a/drivers/net/wireless/realtek/rtw88/tx.c
+++ b/drivers/net/wireless/realtek/rtw88/tx.c
@@ -221,7 +221,7 @@ void rtw_tx_report_handle(struct rtw_dev *rtwdev, struct sk_buff *skb)
 
 static void rtw_tx_mgmt_pkt_info_update(struct rtw_dev *rtwdev,
 					struct rtw_tx_pkt_info *pkt_info,
-					struct ieee80211_tx_control *control,
+					struct ieee80211_sta *sta,
 					struct sk_buff *skb)
 {
 	pkt_info->use_rate = true;
@@ -231,10 +231,9 @@ static void rtw_tx_mgmt_pkt_info_update(struct rtw_dev *rtwdev,
 
 static void rtw_tx_data_pkt_info_update(struct rtw_dev *rtwdev,
 					struct rtw_tx_pkt_info *pkt_info,
-					struct ieee80211_tx_control *control,
+					struct ieee80211_sta *sta,
 					struct sk_buff *skb)
 {
-	struct ieee80211_sta *sta = control->sta;
 	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
 	struct rtw_sta_info *si;
@@ -293,7 +292,7 @@ out:
 
 void rtw_tx_pkt_info_update(struct rtw_dev *rtwdev,
 			    struct rtw_tx_pkt_info *pkt_info,
-			    struct ieee80211_tx_control *control,
+			    struct ieee80211_sta *sta,
 			    struct sk_buff *skb)
 {
 	struct rtw_chip_info *chip = rtwdev->chip;
@@ -305,15 +304,15 @@ void rtw_tx_pkt_info_update(struct rtw_dev *rtwdev,
 	u8 sec_type = 0;
 	bool bmc;
 
-	if (control->sta) {
-		si = (struct rtw_sta_info *)control->sta->drv_priv;
+	if (sta) {
+		si = (struct rtw_sta_info *)sta->drv_priv;
 		vif = si->vif;
 	}
 
 	if (ieee80211_is_mgmt(fc) || ieee80211_is_nullfunc(fc))
-		rtw_tx_mgmt_pkt_info_update(rtwdev, pkt_info, control, skb);
+		rtw_tx_mgmt_pkt_info_update(rtwdev, pkt_info, sta, skb);
 	else if (ieee80211_is_data(fc))
-		rtw_tx_data_pkt_info_update(rtwdev, pkt_info, control, skb);
+		rtw_tx_data_pkt_info_update(rtwdev, pkt_info, sta, skb);
 
 	if (info->control.hw_key) {
 		struct ieee80211_key_conf *key = info->control.hw_key;
@@ -427,10 +426,16 @@ void rtw_tx(struct rtw_dev *rtwdev,
 	    struct sk_buff *skb)
 {
 	struct rtw_tx_pkt_info pkt_info = {0};
+	int ret;
 
-	rtw_tx_pkt_info_update(rtwdev, &pkt_info, control, skb);
-	if (rtw_hci_tx(rtwdev, &pkt_info, skb))
+	rtw_tx_pkt_info_update(rtwdev, &pkt_info, control->sta, skb);
+	ret = rtw_hci_tx_write(rtwdev, &pkt_info, skb);
+	if (ret) {
+		rtw_err(rtwdev, "failed to write TX skb to HCI\n");
 		goto out;
+	}
+
+	rtw_hci_tx_kick_off(rtwdev);
 
 	return;
 
@@ -470,37 +475,61 @@ static void rtw_txq_check_agg(struct rtw_dev *rtwdev,
 	ieee80211_queue_work(rtwdev->hw, &rtwdev->ba_work);
 }
 
-static bool rtw_txq_dequeue(struct rtw_dev *rtwdev,
-			    struct rtw_txq *rtwtxq)
+static int rtw_txq_push_skb(struct rtw_dev *rtwdev,
+			    struct rtw_txq *rtwtxq,
+			    struct sk_buff *skb)
 {
 	struct ieee80211_txq *txq = rtwtxq_to_txq(rtwtxq);
-	struct ieee80211_tx_control control;
-	struct sk_buff *skb;
-
-	skb = ieee80211_tx_dequeue(rtwdev->hw, txq);
-	if (!skb)
-		return false;
+	struct rtw_tx_pkt_info pkt_info = {0};
+	int ret;
 
 	rtw_txq_check_agg(rtwdev, rtwtxq, skb);
 
-	control.sta = txq->sta;
-	rtw_tx(rtwdev, &control, skb);
+	rtw_tx_pkt_info_update(rtwdev, &pkt_info, txq->sta, skb);
+	ret = rtw_hci_tx_write(rtwdev, &pkt_info, skb);
+	if (ret) {
+		rtw_err(rtwdev, "failed to write TX skb to HCI\n");
+		return ret;
+	}
 	rtwtxq->last_push = jiffies;
 
-	return true;
+	return 0;
+}
+
+static struct sk_buff *rtw_txq_dequeue(struct rtw_dev *rtwdev,
+				       struct rtw_txq *rtwtxq)
+{
+	struct ieee80211_txq *txq = rtwtxq_to_txq(rtwtxq);
+	struct sk_buff *skb;
+
+	skb = ieee80211_tx_dequeue(rtwdev->hw, txq);
+	if (!skb)
+		return NULL;
+
+	return skb;
 }
 
 static void rtw_txq_push(struct rtw_dev *rtwdev,
 			 struct rtw_txq *rtwtxq,
 			 unsigned long frames)
 {
+	struct sk_buff *skb;
+	int ret;
 	int i;
 
 	rcu_read_lock();
 
-	for (i = 0; i < frames; i++)
-		if (!rtw_txq_dequeue(rtwdev, rtwtxq))
+	for (i = 0; i < frames; i++) {
+		skb = rtw_txq_dequeue(rtwdev, rtwtxq);
+		if (!skb)
+			break;
+
+		ret = rtw_txq_push_skb(rtwdev, rtwtxq, skb);
+		if (ret) {
+			rtw_err(rtwdev, "failed to pusk skb, ret %d\n", ret);
 			break;
+		}
+	}
 
 	rcu_read_unlock();
 }
@@ -523,6 +552,8 @@ void rtw_tx_tasklet(unsigned long data)
 		list_del_init(&rtwtxq->list);
 	}
 
+	rtw_hci_tx_kick_off(rtwdev);
+
 	spin_unlock_bh(&rtwdev->txq_lock);
 }