From 7a9ca9db400fc95463011449cf47012fb2e1db0d Mon Sep 17 00:00:00 2001
From: Florian Fainelli <f.fainelli@gmail.com>
Date: Sat, 9 Dec 2017 14:59:55 -0800
Subject: [PATCH] net: designware: Pad small packets

Make sure that we pad small packets to a minimum length of 60 bytes
(without FCS). This is necessary to interface with Ethernet switches
that will reject RUNT frames unless padded correctly.

Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
---
 drivers/net/designware.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/net/designware.c b/drivers/net/designware.c
index 9207324..6d53071 100644
--- a/drivers/net/designware.c
+++ b/drivers/net/designware.c
@@ -18,6 +18,7 @@
 #include <pci.h>
 #include <linux/compiler.h>
 #include <linux/err.h>
+#include <linux/kernel.h>
 #include <asm/io.h>
 #include <power/regulator.h>
 #include "designware.h"
@@ -344,6 +345,8 @@ int designware_eth_enable(struct dw_eth_dev *priv)
 	return 0;
 }
 
+#define ETH_ZLEN	60
+
 static int _dw_eth_send(struct dw_eth_dev *priv, void *packet, int length)
 {
 	struct eth_dma_regs *dma_p = priv->dma_regs_p;
@@ -370,6 +373,8 @@ static int _dw_eth_send(struct dw_eth_dev *priv, void *packet, int length)
 		return -EPERM;
 	}
 
+	length = max(length, ETH_ZLEN);
+
 	memcpy((void *)data_start, packet, length);
 
 	/* Flush data to be sent */
-- 
2.7.4