[PATCH net] net: bcmgenet: fix bcmgenet_get_eee() clobbered by phy_ethtool_get_eee()

[Nicolai Buchwitz <nb@tipi-net.de>]

bcmgenet_get_eee() sets the MAC-managed tx_lpi_enabled and tx_lpi_timer
fields, then calls phy_ethtool_get_eee() which internally calls
eeecfg_to_eee() — overwriting eee_enabled, tx_lpi_enabled and
tx_lpi_timer with the PHY's eee_cfg values.  For non-phylink MACs like
GENET, these PHY-level fields are never initialized (they are only set
by phylink via phy_support_eee()), so the ethtool report always shows
eee_enabled=false and tx_lpi_enabled=false regardless of the actual MAC
state.

Reorder the function to call phy_ethtool_get_eee() first, then restore
the MAC-managed fields from the driver's private state.

Fixes: fe0d4fd9285e ("net: phy: Keep track of EEE configuration")
Signed-off-by: Nicolai Buchwitz <nb@tipi-net.de>
---
 drivers/net/ethernet/broadcom/genet/bcmgenet.c | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/broadcom/genet/bcmgenet.c b/drivers/net/ethernet/broadcom/genet/bcmgenet.c
index a71cd729fde6..33fece36a95e 100644
--- a/drivers/net/ethernet/broadcom/genet/bcmgenet.c
+++ b/drivers/net/ethernet/broadcom/genet/bcmgenet.c
@@ -1390,6 +1390,7 @@ static int bcmgenet_get_eee(struct net_device *dev, struct ethtool_keee *e)
 {
 	struct bcmgenet_priv *priv = netdev_priv(dev);
 	struct ethtool_keee *p = &priv->eee;
+	int ret;
 
 	if (GENET_IS_V1(priv))
 		return -EOPNOTSUPP;
@@ -1397,10 +1398,19 @@ static int bcmgenet_get_eee(struct net_device *dev, struct ethtool_keee *e)
 	if (!dev->phydev)
 		return -ENODEV;
 
+	ret = phy_ethtool_get_eee(dev->phydev, e);
+	if (ret)
+		return ret;
+
+	/* Restore MAC-managed fields that phy_ethtool_get_eee() overwrites
+	 * with the PHY's eee_cfg (which is only set by phylink-managed MACs
+	 * via phy_support_eee()).
+	 */
+	e->eee_enabled = p->eee_enabled;
 	e->tx_lpi_enabled = p->tx_lpi_enabled;
 	e->tx_lpi_timer = bcmgenet_umac_readl(priv, UMAC_EEE_LPI_TIMER);
 
-	return phy_ethtool_get_eee(dev->phydev, e);
+	return 0;
 }
 
 static int bcmgenet_set_eee(struct net_device *dev, struct ethtool_keee *e)
-- 
2.51.0