net: bcmgenet: Fix EEE implementation

We had a number of short comings:

- EEE must be re-evaluated whenever the state machine detects a link
  change as wight be switching from a link partner with EEE
  enabled/disabled

- tx_lpi_enabled controls whether EEE should be enabled/disabled for the
  transmit path, which applies to the TBUF block

- We do not need to forcibly enable EEE upon system resume, as the PHY
  state machine will trigger a link event that will do that, too

Fixes: 6ef398e ("net: bcmgenet: add EEE support")
Signed-off-by: Florian Fainelli <florian.fainelli@broadcom.com>
Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Link: https://lore.kernel.org/r/20230606214348.2408018-1-florian.fainelli@broadcom.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Author: ffainelli

drivers/net/ethernet/broadcom/genet/bcmgenet.c

@@ -1272,7 +1272,8 @@ static void bcmgenet_get_ethtool_stats(struct net_device *dev,
 	}
 }
 
-static void bcmgenet_eee_enable_set(struct net_device *dev, bool enable)
+void bcmgenet_eee_enable_set(struct net_device *dev, bool enable,
+			     bool tx_lpi_enabled)
 {
 	struct bcmgenet_priv *priv = netdev_priv(dev);
 	u32 off = priv->hw_params->tbuf_offset + TBUF_ENERGY_CTRL;
@@ -1292,7 +1293,7 @@ static void bcmgenet_eee_enable_set(struct net_device *dev, bool enable)
 
 	/* Enable EEE and switch to a 27Mhz clock automatically */
 	reg = bcmgenet_readl(priv->base + off);
-	if (enable)
+	if (tx_lpi_enabled)
 		reg |= TBUF_EEE_EN | TBUF_PM_EN;
 	else
 		reg &= ~(TBUF_EEE_EN | TBUF_PM_EN);
@@ -1313,6 +1314,7 @@ static void bcmgenet_eee_enable_set(struct net_device *dev, bool enable)
 
 	priv->eee.eee_enabled = enable;
 	priv->eee.eee_active = enable;
+	priv->eee.tx_lpi_enabled = tx_lpi_enabled;
 }
 
 static int bcmgenet_get_eee(struct net_device *dev, struct ethtool_eee *e)
@@ -1328,6 +1330,7 @@ static int bcmgenet_get_eee(struct net_device *dev, struct ethtool_eee *e)
 
 	e->eee_enabled = p->eee_enabled;
 	e->eee_active = p->eee_active;
+	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);
@@ -1337,7 +1340,6 @@ static int bcmgenet_set_eee(struct net_device *dev, struct ethtool_eee *e)
 {
 	struct bcmgenet_priv *priv = netdev_priv(dev);
 	struct ethtool_eee *p = &priv->eee;
-	int ret = 0;
 
 	if (GENET_IS_V1(priv))
 		return -EOPNOTSUPP;
@@ -1348,16 +1350,11 @@ static int bcmgenet_set_eee(struct net_device *dev, struct ethtool_eee *e)
 	p->eee_enabled = e->eee_enabled;
 
 	if (!p->eee_enabled) {
-		bcmgenet_eee_enable_set(dev, false);
+		bcmgenet_eee_enable_set(dev, false, false);
 	} else {
-		ret = phy_init_eee(dev->phydev, false);
-		if (ret) {
-			netif_err(priv, hw, dev, "EEE initialization failed\n");
-			return ret;
-		}
-
+		p->eee_active = phy_init_eee(dev->phydev, false) >= 0;
 		bcmgenet_umac_writel(priv, e->tx_lpi_timer, UMAC_EEE_LPI_TIMER);
-		bcmgenet_eee_enable_set(dev, true);
+		bcmgenet_eee_enable_set(dev, p->eee_active, e->tx_lpi_enabled);
 	}
 
 	return phy_ethtool_set_eee(dev->phydev, e);
@@ -4279,9 +4276,6 @@ static int bcmgenet_resume(struct device *d)
 	if (!device_may_wakeup(d))
 		phy_resume(dev->phydev);
 
-	if (priv->eee.eee_enabled)
-		bcmgenet_eee_enable_set(dev, true);
-
 	bcmgenet_netif_start(dev);
 
 	netif_device_attach(dev);

drivers/net/ethernet/broadcom/genet/bcmgenet.h

@@ -703,4 +703,7 @@ int bcmgenet_wol_power_down_cfg(struct bcmgenet_priv *priv,
 void bcmgenet_wol_power_up_cfg(struct bcmgenet_priv *priv,
 			       enum bcmgenet_power_mode mode);
 
+void bcmgenet_eee_enable_set(struct net_device *dev, bool enable,
+			     bool tx_lpi_enabled);
+
 #endif /* __BCMGENET_H__ */

drivers/net/ethernet/broadcom/genet/bcmmii.c

@@ -87,6 +87,11 @@ static void bcmgenet_mac_config(struct net_device *dev)
 		reg |= CMD_TX_EN | CMD_RX_EN;
 	}
 	bcmgenet_umac_writel(priv, reg, UMAC_CMD);
+
+	priv->eee.eee_active = phy_init_eee(phydev, 0) >= 0;
+	bcmgenet_eee_enable_set(dev,
+				priv->eee.eee_enabled && priv->eee.eee_active,
+				priv->eee.tx_lpi_enabled);
 }
 
 /* setup netdev link state when PHY link status change and