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, 45 insertions, 0 deletions

diff --git a/target/linux/bcm63xx/patches-5.4/043-v5.12-bcm63xx_enet-alloc-rx-skb-with-NET_IP_ALIGN.patch b/target/linux/bcm63xx/patches-5.4/043-v5.12-bcm63xx_enet-alloc-rx-skb-with-NET_IP_ALIGN.patch
new file mode 100644
index 0000000000..575dcb9ad8
--- /dev/null
+++ b/target/linux/bcm63xx/patches-5.4/043-v5.12-bcm63xx_enet-alloc-rx-skb-with-NET_IP_ALIGN.patch
@@ -0,0 +1,45 @@
+From c4a207865e7ea310dc146ff4aa1b0aa0c78d3fe1 Mon Sep 17 00:00:00 2001
+From: Sieng Piaw Liew <liew.s.piaw@gmail.com>
+Date: Wed, 6 Jan 2021 22:42:05 +0800
+Subject: [PATCH 4/7] bcm63xx_enet: alloc rx skb with NET_IP_ALIGN
+
+Use netdev_alloc_skb_ip_align on newer SoCs with integrated switch
+(enetsw) when refilling RX. Increases packet processing performance
+by 30% (with netif_receive_skb_list).
+
+Non-enetsw SoCs cannot function with the extra pad so continue to use
+the regular netdev_alloc_skb.
+
+Tested on BCM6328 320 MHz and iperf3 -M 512 to measure packet/sec
+performance.
+
+Before:
+[ ID] Interval Transfer Bandwidth Retr
+[ 4] 0.00-30.00 sec 120 MBytes 33.7 Mbits/sec 277 sender
+[ 4] 0.00-30.00 sec 120 MBytes 33.5 Mbits/sec receiver
+
+After (+netif_receive_skb_list):
+[ 4] 0.00-30.00 sec 155 MBytes 43.3 Mbits/sec 354 sender
+[ 4] 0.00-30.00 sec 154 MBytes 43.1 Mbits/sec receiver
+
+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 | 5 ++++-
+ 1 file changed, 4 insertions(+), 1 deletion(-)
+
+--- a/drivers/net/ethernet/broadcom/bcm63xx_enet.c
++++ b/drivers/net/ethernet/broadcom/bcm63xx_enet.c
+@@ -238,7 +238,10 @@ static int bcm_enet_refill_rx(struct net
+ 		desc = &priv->rx_desc_cpu[desc_idx];
+ 
+ 		if (!priv->rx_skb[desc_idx]) {
+-			skb = netdev_alloc_skb(dev, priv->rx_skb_size);
++			if (priv->enet_is_sw)
++				skb = netdev_alloc_skb_ip_align(dev, priv->rx_skb_size);
++			else
++				skb = netdev_alloc_skb(dev, priv->rx_skb_size);
+ 			if (!skb)
+ 				break;
+ 			priv->rx_skb[desc_idx] = skb;