From: Jose Abreu <Jose.Abreu@synopsys.com>
Date: Thu, 5 Sep 2019 13:43:10 +0200
Subject: net: phy: Do not check Link status when loopback is enabled
Patch-mainline: v5.4-rc1
Git-commit: fe4a7a41767a14dbb148e41b0659be38a696fe07
References: bsc#1176447

While running stmmac selftests I found that in my 1G setup some tests
were failling when running with PHY loopback enabled.

It looks like when loopback is enabled the PHY will report that Link is
down even though there is a valid connection.

As in loopback mode the data will not be sent anywhere we can bypass the
logic of checking if Link is valid thus saving unecessary reads.

Signed-off-by: Jose Abreu <joabreu@synopsys.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 drivers/net/phy/phy.c |    6 ++++++
 1 file changed, 6 insertions(+)

--- a/drivers/net/phy/phy.c
+++ b/drivers/net/phy/phy.c
@@ -525,6 +525,12 @@ static int phy_check_link_status(struct
 
 	WARN_ON(!mutex_is_locked(&phydev->lock));
 
+	/* Keep previous state if loopback is enabled because some PHYs
+	 * report that Link is Down when loopback is enabled.
+	 */
+	if (phydev->loopback_enabled)
+		return 0;
+
 	err = phy_read_status(phydev);
 	if (err)
 		return err;