From 330126d68d1ecd63fb8ff10f6e3962a945610faf Mon Sep 17 00:00:00 2001
From: David Wu <david.wu@rock-chips.com>
Date: Wed, 10 Apr 2019 11:43:11 +0800
Subject: [PATCH] net: ethernet: stmmac: Workaround for tx checksum error

Change-Id: Ib0f45ff087e7e7e1c5ef9869b316441314151478
Signed-off-by: David Wu <david.wu@rock-chips.com>
---
 .../net/ethernet/stmicro/stmmac/stmmac_main.c | 27 +++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index 22748ea4498f..965a9d6a2c41 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -1942,6 +1942,23 @@ static int stmmac_release(struct net_device *dev)
 	return 0;
 }
 
+static bool stmmac_tx_skb_need_linearize(struct sk_buff *skb, struct net_device *dev)
+{
+	int nfrags = skb_shinfo(skb)->nr_frags, i;
+
+	if (skb->len != dev->mtu + ETH_HLEN)
+		return false;
+
+	for (i = 0; i < nfrags; i++) {
+		const skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
+
+		if (!IS_ALIGNED((unsigned long)frag->page_offset, 4))
+			return true;
+	}
+
+	return false;
+}
+
 /**
  *  stmmac_xmit - Tx entry point of the driver
  *  @skb : the socket buffer
@@ -1973,6 +1990,16 @@ static netdev_tx_t stmmac_xmit(struct sk_buff *skb, struct net_device *dev)
 		return NETDEV_TX_BUSY;
 	}
 
+	if (stmmac_tx_skb_need_linearize(skb, dev)) {
+		if (skb_linearize(skb)) {
+			spin_unlock(&priv->tx_lock);
+			return NETDEV_TX_BUSY;
+		} else {
+			nfrags = skb_shinfo(skb)->nr_frags;
+			nopaged_len = skb_headlen(skb);
+		}
+	}
+
 	if (priv->tx_path_in_lpi_mode)
 		stmmac_disable_eee_mode(priv);
 
-- 
2.19.1