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

drivers/net/wireless/realtek/rtw88/hci.h

···
 
 /* ops for PCI, USB and SDIO */
 struct rtw_hci_ops {
-	int (*tx)(struct rtw_dev *rtwdev,
-		  struct rtw_tx_pkt_info *pkt_info,
-		  struct sk_buff *skb);
+	int (*tx_write)(struct rtw_dev *rtwdev,
+			struct rtw_tx_pkt_info *pkt_info,
+			struct sk_buff *skb);
+	void (*tx_kick_off)(struct rtw_dev *rtwdev);
 	int (*setup)(struct rtw_dev *rtwdev);
 	int (*start)(struct rtw_dev *rtwdev);
 	void (*stop)(struct rtw_dev *rtwdev);
···
 	void (*write32)(struct rtw_dev *rtwdev, u32 addr, u32 val);
 };
 
-static inline int rtw_hci_tx(struct rtw_dev *rtwdev,
-			     struct rtw_tx_pkt_info *pkt_info,
-			     struct sk_buff *skb)
+static inline int rtw_hci_tx_write(struct rtw_dev *rtwdev,
+				   struct rtw_tx_pkt_info *pkt_info,
+				   struct sk_buff *skb)
 {
-	return rtwdev->hci.ops->tx(rtwdev, pkt_info, skb);
+	return rtwdev->hci.ops->tx_write(rtwdev, pkt_info, skb);
+}
+
+static inline void rtw_hci_tx_kick_off(struct rtw_dev *rtwdev)
+{
+	return rtwdev->hci.ops->tx_kick_off(rtwdev);
 }
 
 static inline int rtw_hci_setup(struct rtw_dev *rtwdev)

drivers/net/wireless/realtek/rtw88/pci.c

···
 	rtwpci->rx_tag = (rtwpci->rx_tag + 1) % RX_TAG_MAX;
 }
 
-static int rtw_pci_xmit(struct rtw_dev *rtwdev,
-			struct rtw_tx_pkt_info *pkt_info,
-			struct sk_buff *skb, u8 queue)
+static void rtw_pci_tx_kick_off_queue(struct rtw_dev *rtwdev, u8 queue)
+{
+	struct rtw_pci *rtwpci = (struct rtw_pci *)rtwdev->priv;
+	struct rtw_pci_tx_ring *ring;
+	u32 bd_idx;
+
+	ring = &rtwpci->tx_rings[queue];
+	bd_idx = rtw_pci_tx_queue_idx_addr[queue];
+
+	spin_lock_bh(&rtwpci->irq_lock);
+	rtw_pci_deep_ps_leave(rtwdev);
+	rtw_write16(rtwdev, bd_idx, ring->r.wp & TRX_BD_IDX_MASK);
+	spin_unlock_bh(&rtwpci->irq_lock);
+}
+
+static void rtw_pci_tx_kick_off(struct rtw_dev *rtwdev)
+{
+	struct rtw_pci *rtwpci = (struct rtw_pci *)rtwdev->priv;
+	u8 queue;
+
+	for (queue = 0; queue < RTK_MAX_TX_QUEUE_NUM; queue++)
+		if (test_and_clear_bit(queue, rtwpci->tx_queued))
+			rtw_pci_tx_kick_off_queue(rtwdev, queue);
+}
+
+static int rtw_pci_tx_write_data(struct rtw_dev *rtwdev,
+				 struct rtw_tx_pkt_info *pkt_info,
+				 struct sk_buff *skb, u8 queue)
 {
 	struct rtw_pci *rtwpci = (struct rtw_pci *)rtwdev->priv;
 	struct rtw_chip_info *chip = rtwdev->chip;
···
 	u32 psb_len;
 	u8 *pkt_desc;
 	struct rtw_pci_tx_buffer_desc *buf_desc;
-	u32 bd_idx;
 
 	ring = &rtwpci->tx_rings[queue];
 
···
 
 	spin_lock_bh(&rtwpci->irq_lock);
 
-	rtw_pci_deep_ps_leave(rtwdev);
 	skb_queue_tail(&ring->queue, skb);
 
-	/* kick off tx queue */
-	if (queue != RTW_TX_QUEUE_BCN) {
-		if (++ring->r.wp >= ring->r.len)
-			ring->r.wp = 0;
-		bd_idx = rtw_pci_tx_queue_idx_addr[queue];
-		rtw_write16(rtwdev, bd_idx, ring->r.wp & TRX_BD_IDX_MASK);
-	} else {
-		u32 reg_bcn_work;
+	if (queue == RTW_TX_QUEUE_BCN)
+		goto out_unlock;
 
-		reg_bcn_work = rtw_read8(rtwdev, RTK_PCI_TXBD_BCN_WORK);
-		reg_bcn_work |= BIT_PCI_BCNQ_FLAG;
-		rtw_write8(rtwdev, RTK_PCI_TXBD_BCN_WORK, reg_bcn_work);
-	}
+	/* update write-index, and kick it off later */
+	set_bit(queue, rtwpci->tx_queued);
+	if (++ring->r.wp >= ring->r.len)
+		ring->r.wp = 0;
+
+out_unlock:
 	spin_unlock_bh(&rtwpci->irq_lock);
 
 	return 0;
···
 {
 	struct sk_buff *skb;
 	struct rtw_tx_pkt_info pkt_info = {0};
+	u8 reg_bcn_work;
+	int ret;
 
 	skb = rtw_tx_write_data_rsvd_page_get(rtwdev, &pkt_info, buf, size);
 	if (!skb)
 		return -ENOMEM;
 
-	return rtw_pci_xmit(rtwdev, &pkt_info, skb, RTW_TX_QUEUE_BCN);
+	ret = rtw_pci_tx_write_data(rtwdev, &pkt_info, skb, RTW_TX_QUEUE_BCN);
+	if (ret) {
+		rtw_err(rtwdev, "failed to write rsvd page data\n");
+		return ret;
+	}
+
+	/* reserved pages go through beacon queue */
+	reg_bcn_work = rtw_read8(rtwdev, RTK_PCI_TXBD_BCN_WORK);
+	reg_bcn_work |= BIT_PCI_BCNQ_FLAG;
+	rtw_write8(rtwdev, RTK_PCI_TXBD_BCN_WORK, reg_bcn_work);
+
+	return 0;
 }
 
 static int rtw_pci_write_data_h2c(struct rtw_dev *rtwdev, u8 *buf, u32 size)
 {
 	struct sk_buff *skb;
 	struct rtw_tx_pkt_info pkt_info = {0};
+	int ret;
 
 	skb = rtw_tx_write_data_h2c_get(rtwdev, &pkt_info, buf, size);
 	if (!skb)
 		return -ENOMEM;
 
-	return rtw_pci_xmit(rtwdev, &pkt_info, skb, RTW_TX_QUEUE_H2C);
+	ret = rtw_pci_tx_write_data(rtwdev, &pkt_info, skb, RTW_TX_QUEUE_H2C);
+	if (ret) {
+		rtw_err(rtwdev, "failed to write h2c data\n");
+		return ret;
+	}
+
+	rtw_pci_tx_kick_off_queue(rtwdev, RTW_TX_QUEUE_H2C);
+
+	return 0;
 }
 
-static int rtw_pci_tx(struct rtw_dev *rtwdev,
-		      struct rtw_tx_pkt_info *pkt_info,
-		      struct sk_buff *skb)
+static int rtw_pci_tx_write(struct rtw_dev *rtwdev,
+			    struct rtw_tx_pkt_info *pkt_info,
+			    struct sk_buff *skb)
 {
 	struct rtw_pci *rtwpci = (struct rtw_pci *)rtwdev->priv;
 	struct rtw_pci_tx_ring *ring;
 	u8 queue = rtw_hw_queue_mapping(skb);
 	int ret;
 
-	ret = rtw_pci_xmit(rtwdev, pkt_info, skb, queue);
+	ret = rtw_pci_tx_write_data(rtwdev, pkt_info, skb, queue);
 	if (ret)
 		return ret;
 
···
 }
 
 static struct rtw_hci_ops rtw_pci_ops = {
-	.tx = rtw_pci_tx,
+	.tx_write = rtw_pci_tx_write,
+	.tx_kick_off = rtw_pci_tx_kick_off,
 	.setup = rtw_pci_setup,
 	.start = rtw_pci_start,
 	.stop = rtw_pci_stop,

drivers/net/wireless/realtek/rtw88/pci.h

···
 	bool irq_enabled;
 
 	u16 rx_tag;
+	DECLARE_BITMAP(tx_queued, RTK_MAX_TX_QUEUE_NUM);
 	struct rtw_pci_tx_ring tx_rings[RTK_MAX_TX_QUEUE_NUM];
 	struct rtw_pci_rx_ring rx_rings[RTK_MAX_RX_QUEUE_NUM];
 	u16 link_ctrl;

drivers/net/wireless/realtek/rtw88/tx.c

···
 
 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;
···
 
 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;
···
 
 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;
···
 	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;
···
 	    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;
 
···
 	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 rtw_tx_pkt_info pkt_info = {0};
+	int ret;
+
+	rtw_txq_check_agg(rtwdev, rtwtxq, 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 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 false;
+		return NULL;
 
-	rtw_txq_check_agg(rtwdev, rtwtxq, skb);
-
-	control.sta = txq->sta;
-	rtw_tx(rtwdev, &control, skb);
-	rtwtxq->last_push = jiffies;
-
-	return true;
+	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();
 }
···
 
 		list_del_init(&rtwtxq->list);
 	}
+
+	rtw_hci_tx_kick_off(rtwdev);
 
 	spin_unlock_bh(&rtwdev->txq_lock);
 }

drivers/net/wireless/realtek/rtw88/tx.h

···
 void rtw_tx_tasklet(unsigned long data);
 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);
 void rtw_tx_fill_tx_desc(struct rtw_tx_pkt_info *pkt_info, struct sk_buff *skb);
 void rtw_tx_report_enqueue(struct rtw_dev *rtwdev, struct sk_buff *skb, u8 sn);