bcm63xx_enet: add BQL support

Add Byte Queue Limits support to reduce/remove bufferbloat in
bcm63xx_enet.

Signed-off-by: Sieng Piaw Liew <liew.s.piaw@gmail.com>
Acked-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/ethernet/broadcom/bcm63xx_enet.c

@@ -417,9 +417,11 @@ static int bcm_enet_receive_queue(struct net_device *dev, int budget)
 static int bcm_enet_tx_reclaim(struct net_device *dev, int force)
 {
 	struct bcm_enet_priv *priv;
+	unsigned int bytes;
 	int released;
 
 	priv = netdev_priv(dev);
+	bytes = 0;
 	released = 0;
 
 	while (priv->tx_desc_count < priv->tx_ring_size) {
@@ -456,10 +458,13 @@ static int bcm_enet_tx_reclaim(struct net_device *dev, int force)
 		if (desc->len_stat & DMADESC_UNDER_MASK)
 			dev->stats.tx_errors++;
 
+		bytes += skb->len;
 		dev_kfree_skb(skb);
 		released++;
 	}
 
+	netdev_completed_queue(dev, released, bytes);
+
 	if (netif_queue_stopped(dev) && released)
 		netif_wake_queue(dev);
 
@@ -626,6 +631,8 @@ bcm_enet_start_xmit(struct sk_buff *skb, struct net_device *dev)
 	desc->len_stat = len_stat;
 	wmb();
 
+	netdev_sent_queue(dev, skb->len);
+
 	/* kick tx dma */
 	enet_dmac_writel(priv, priv->dma_chan_en_mask,
 				 ENETDMAC_CHANCFG, priv->tx_chan);
@@ -1169,6 +1176,7 @@ static int bcm_enet_stop(struct net_device *dev)
 	kdev = &priv->pdev->dev;
 
 	netif_stop_queue(dev);
+	netdev_reset_queue(dev);
 	napi_disable(&priv->napi);
 	if (priv->has_phy)
 		phy_stop(dev->phydev);
@@ -2338,6 +2346,7 @@ static int bcm_enetsw_stop(struct net_device *dev)
 
 	del_timer_sync(&priv->swphy_poll);
 	netif_stop_queue(dev);
+	netdev_reset_queue(dev);
 	napi_disable(&priv->napi);
 	del_timer_sync(&priv->rx_timeout);