net: emac: fix fixed-link setup for the RTL8363SB switch

[ Upstream commit 08e39982 ]

On the Netgear WNDAP620, the emac ethernet isn't receiving nor
xmitting any frames from/to the RTL8363SB (identifies itself
as a RTL8367RB).

This is caused by the emac hardware not knowing the forced link
parameters for speed, duplex, pause, etc.

This begs the question, how this was working on the original
driver code, when it was necessary to set the phy_address and
phy_map to 0xffffffff. But I guess without access to the old
PPC405/440/460 hardware, it's not possible to know.
Signed-off-by: Christian Lamparter <chunkeey@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/net/ethernet/ibm/emac/core.c

@@ -2671,12 +2671,17 @@ static int emac_init_phy(struct emac_instance *dev)
 		if (of_phy_is_fixed_link(np)) {
 			int res = emac_dt_mdio_probe(dev);
 
-			if (!res) {
-				res = of_phy_register_fixed_link(np);
-				if (res)
-					mdiobus_unregister(dev->mii_bus);
+			if (res)
+				return res;
+
+			res = of_phy_register_fixed_link(np);
+			dev->phy_dev = of_phy_find_device(np);
+			if (res || !dev->phy_dev) {
+				mdiobus_unregister(dev->mii_bus);
+				return res ? res : -EINVAL;
 			}
-			return res;
+			emac_adjust_link(dev->ndev);
+			put_device(&dev->phy_dev->mdio.dev);
 		}
 		return 0;
 	}