bcm63xx: sync ethernet driver with net-next

Sync ethernet driver code with upstream Linux kernel:
-Reduce xmit_more code changes.
-Combine rx cleanup code into a function.
-Convert to build_skb.
-Improve rx loop by optimizing loop tracking.

https://lore.kernel.org/netdev/20210106144208.1935-1-liew.s.piaw@gmail.com/
Signed-off-by: Sieng Piaw Liew <liew.s.piaw@gmail.com>
[Amend commit description, move patches to the top since they are going to be
upstreamed]
Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>

1 files changed, 68 insertions, 0 deletions

diff --git a/target/linux/bcm63xx/patches-5.4/041-v5.12-bcm63xx_enet-add-BQL-support.patch b/target/linux/bcm63xx/patches-5.4/041-v5.12-bcm63xx_enet-add-BQL-support.patch
new file mode 100644
index 0000000000..f55aa8fe17
--- /dev/null
+++ b/target/linux/bcm63xx/patches-5.4/041-v5.12-bcm63xx_enet-add-BQL-support.patch
@@ -0,0 +1,68 @@
+From 4c59b0f5543db80abbbe9efdd9b25e7899501db5 Mon Sep 17 00:00:00 2001
+From: Sieng Piaw Liew <liew.s.piaw@gmail.com>
+Date: Wed, 6 Jan 2021 22:42:03 +0800
+Subject: [PATCH 2/7] 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 | 9 +++++++++
+ 1 file changed, 9 insertions(+)
+
+--- a/drivers/net/ethernet/broadcom/bcm63xx_enet.c
++++ b/drivers/net/ethernet/broadcom/bcm63xx_enet.c
+@@ -418,9 +418,11 @@ static int bcm_enet_receive_queue(struct
+ 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) {
+@@ -457,10 +459,13 @@ static int bcm_enet_tx_reclaim(struct ne
+ 		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);
+ 
+@@ -627,6 +632,8 @@ bcm_enet_start_xmit(struct sk_buff *skb,
+ 	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);
+@@ -1170,6 +1177,7 @@ static int bcm_enet_stop(struct net_devi
+ 	kdev = &priv->pdev->dev;
+ 
+ 	netif_stop_queue(dev);
++	netdev_reset_queue(dev);
+ 	napi_disable(&priv->napi);
+ 	if (priv->has_phy)
+ 		phy_stop(dev->phydev);
+@@ -2343,6 +2351,7 @@ static int bcm_enetsw_stop(struct net_de
+ 
+ 	del_timer_sync(&priv->swphy_poll);
+ 	netif_stop_queue(dev);
++	netdev_reset_queue(dev);
+ 	napi_disable(&priv->napi);
+ 	del_timer_sync(&priv->rx_timeout);
+