From: Bhadram Varka <vbhadram@nvidia.com>
Date: Sun, 17 Jun 2018 20:02:05 +0530
Subject: stmmac: fix DMA channel hang in half-duplex mode
Git-commit: b6cfffa7ad923c73f317ea50fd4ebcb3b4b6669c
Patch-mainline: v4.18-rc2
References: networking-stable-18_07_19

HW does not support Half-duplex mode in multi-queue
scenario. Fix it by not advertising the Half-Duplex
mode if multi-queue enabled.

Signed-off-by: Bhadram Varka <vbhadram@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
 drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index e79b0d7b388a..cba46b62a1cd 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -928,6 +928,7 @@ static void stmmac_check_pcs_mode(struct stmmac_priv *priv)
 static int stmmac_init_phy(struct net_device *dev)
 {
 	struct stmmac_priv *priv = netdev_priv(dev);
+	u32 tx_cnt = priv->plat->tx_queues_to_use;
 	struct phy_device *phydev;
 	char phy_id_fmt[MII_BUS_ID_SIZE + 3];
 	char bus_id[MII_BUS_ID_SIZE];
@@ -968,6 +969,15 @@ static int stmmac_init_phy(struct net_device *dev)
 		phydev->advertising &= ~(SUPPORTED_1000baseT_Half |
 					 SUPPORTED_1000baseT_Full);
 
+	/*
+	 * Half-duplex mode not supported with multiqueue
+	 * half-duplex can only works with single queue
+	 */
+	if (tx_cnt > 1)
+		phydev->supported &= ~(SUPPORTED_1000baseT_Half |
+				       SUPPORTED_100baseT_Half |
+				       SUPPORTED_10baseT_Half);
+
 	/*
 	 * Broken HW is sometimes missing the pull-up resistor on the
 	 * MDIO line, which results in reads to non-existent devices returning
-- 
2.18.0