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, 26 insertions, 0 deletions

diff --git a/target/linux/bcm63xx/patches-5.4/042-v5.12-bcm63xx_enet-add-xmit_more-support.patch b/target/linux/bcm63xx/patches-5.4/042-v5.12-bcm63xx_enet-add-xmit_more-support.patch
new file mode 100644
index 0000000000..4b02cd7849
--- /dev/null
+++ b/target/linux/bcm63xx/patches-5.4/042-v5.12-bcm63xx_enet-add-xmit_more-support.patch
@@ -0,0 +1,26 @@
+From 375281d3a6dcabaa98f489ee412aedca6d99dffb Mon Sep 17 00:00:00 2001
+From: Sieng Piaw Liew <liew.s.piaw@gmail.com>
+Date: Wed, 6 Jan 2021 22:42:04 +0800
+Subject: [PATCH 3/7] bcm63xx_enet: add xmit_more support
+
+Support bulking hardware TX queue by using netdev_xmit_more().
+
+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 | 3 ++-
+ 1 file changed, 2 insertions(+), 1 deletion(-)
+
+--- a/drivers/net/ethernet/broadcom/bcm63xx_enet.c
++++ b/drivers/net/ethernet/broadcom/bcm63xx_enet.c
+@@ -635,7 +635,8 @@ bcm_enet_start_xmit(struct sk_buff *skb,
+ 	netdev_sent_queue(dev, skb->len);
+ 
+ 	/* kick tx dma */
+-	enet_dmac_writel(priv, priv->dma_chan_en_mask,
++	if (!netdev_xmit_more() || !priv->tx_desc_count)
++		enet_dmac_writel(priv, priv->dma_chan_en_mask,
+ 				 ENETDMAC_CHANCFG, priv->tx_chan);
+ 
+ 	/* stop queue if no more desc available */