[PATCH net-next v2 1/1] net: sxgbe: rework EEE handling based on PHY negotiation

[Oleksij Rempel]

From: Andrew Lunn <andrew@xxxxxxx>

Rework EEE handling to depend on PHY negotiation results. Enable EEE
only after a valid link is established and allow proper LPI mode
activation.

Previously, sxgbe_eee_init() was called in sxgbe_open() to invoke
phy_init_eee() most probably before the PHY could complete
auto-negotiation. Non-automotive PHYs typically take ~1 sec to
establish a link, so EEE was rarely enabled.

Now, EEE activation is deferred until after PHY negotiation.  The driver
delegates EEE control to phylib via ethtool set/get calls. Timer values
are taken from phydev->eee_cfg.tx_lpi_timer, and sxgbe_eee_adjust()
configures EEE based on phydev->enable_tx_lpi and the PHY link status.

This activation of LPI may reveal issues that were hidden when LPI was
rarely active.

WARNING: This patch is only compile tested.

Signed-off-by: Andrew Lunn <andrew@xxxxxxx>
Signed-off-by: Oleksij Rempel <o.rempel@xxxxxxxxxxxxxx>
---
changes v2:
- major rework with many changes
- use phydev->eee_cfg.tx_lpi_timer where possible
- drop sxgbe_eee_init() and rework sxgbe_eee_adjust()
---
 .../net/ethernet/samsung/sxgbe/sxgbe_common.h |  2 -
 .../ethernet/samsung/sxgbe/sxgbe_ethtool.c    | 22 +-----
 .../net/ethernet/samsung/sxgbe/sxgbe_main.c   | 69 +++++++------------
 3 files changed, 26 insertions(+), 67 deletions(-)

diff --git a/drivers/net/ethernet/samsung/sxgbe/sxgbe_common.h b/drivers/net/ethernet/samsung/sxgbe/sxgbe_common.h
index 1458939c3bf5..a8eed188d110 100644
--- a/drivers/net/ethernet/samsung/sxgbe/sxgbe_common.h
+++ b/drivers/net/ethernet/samsung/sxgbe/sxgbe_common.h
@@ -526,6 +526,4 @@ int sxgbe_restore(struct net_device *ndev);
 
 const struct sxgbe_mtl_ops *sxgbe_get_mtl_ops(void);
 
-void sxgbe_disable_eee_mode(struct sxgbe_priv_data * const priv);
-bool sxgbe_eee_init(struct sxgbe_priv_data * const priv);
 #endif /* __SXGBE_COMMON_H__ */
diff --git a/drivers/net/ethernet/samsung/sxgbe/sxgbe_ethtool.c b/drivers/net/ethernet/samsung/sxgbe/sxgbe_ethtool.c
index 4a439b34114d..a13360962e47 100644
--- a/drivers/net/ethernet/samsung/sxgbe/sxgbe_ethtool.c
+++ b/drivers/net/ethernet/samsung/sxgbe/sxgbe_ethtool.c
@@ -140,8 +140,6 @@ static int sxgbe_get_eee(struct net_device *dev,
 	if (!priv->hw_cap.eee)
 		return -EOPNOTSUPP;
 
-	edata->tx_lpi_timer = priv->tx_lpi_timer;
-
 	return phy_ethtool_get_eee(dev->phydev, edata);
 }
 
@@ -150,22 +148,8 @@ static int sxgbe_set_eee(struct net_device *dev,
 {
 	struct sxgbe_priv_data *priv = netdev_priv(dev);
 
-	priv->eee_enabled = edata->eee_enabled;
-
-	if (!priv->eee_enabled) {
-		sxgbe_disable_eee_mode(priv);
-	} else {
-		/* We are asking for enabling the EEE but it is safe
-		 * to verify all by invoking the eee_init function.
-		 * In case of failure it will return an error.
-		 */
-		priv->eee_enabled = sxgbe_eee_init(priv);
-		if (!priv->eee_enabled)
-			return -EOPNOTSUPP;
-
-		/* Do not change tx_lpi_timer in case of failure */
-		priv->tx_lpi_timer = edata->tx_lpi_timer;
-	}
+	if (!priv->hw_cap.eee)
+		return -EOPNOTSUPP;
 
 	return phy_ethtool_set_eee(dev->phydev, edata);
 }
@@ -228,7 +212,7 @@ static void sxgbe_get_ethtool_stats(struct net_device *dev,
 	int i;
 	char *p;
 
-	if (priv->eee_enabled) {
+	if (dev->phydev->eee_active) {
 		int val = phy_get_eee_err(dev->phydev);
 
 		if (val)
diff --git a/drivers/net/ethernet/samsung/sxgbe/sxgbe_main.c b/drivers/net/ethernet/samsung/sxgbe/sxgbe_main.c
index 12c8396b6942..8a385c92a6d1 100644
--- a/drivers/net/ethernet/samsung/sxgbe/sxgbe_main.c
+++ b/drivers/net/ethernet/samsung/sxgbe/sxgbe_main.c
@@ -87,7 +87,7 @@ static void sxgbe_enable_eee_mode(const struct sxgbe_priv_data *priv)
 		priv->hw->mac->set_eee_mode(priv->ioaddr);
 }
 
-void sxgbe_disable_eee_mode(struct sxgbe_priv_data * const priv)
+static void sxgbe_disable_eee_mode(struct sxgbe_priv_data * const priv)
 {
 	/* Exit and disable EEE in case of we are in LPI state. */
 	priv->hw->mac->reset_eee_mode(priv->ioaddr);
@@ -110,52 +110,25 @@ static void sxgbe_eee_ctrl_timer(struct timer_list *t)
 	mod_timer(&priv->eee_ctrl_timer, SXGBE_LPI_TIMER(eee_timer));
 }
 
-/**
- * sxgbe_eee_init
- * @priv: private device pointer
- * Description:
- *  If the EEE support has been enabled while configuring the driver,
- *  if the GMAC actually supports the EEE (from the HW cap reg) and the
- *  phy can also manage EEE, so enable the LPI state and start the timer
- *  to verify if the tx path can enter in LPI state.
- */
-bool sxgbe_eee_init(struct sxgbe_priv_data * const priv)
+static void sxgbe_eee_adjust(struct sxgbe_priv_data *priv)
 {
-	struct net_device *ndev = priv->dev;
-	bool ret = false;
+	struct phy_device *phydev = priv->dev->phydev;
 
-	/* MAC core supports the EEE feature. */
-	if (priv->hw_cap.eee) {
-		/* Check if the PHY supports EEE */
-		if (phy_init_eee(ndev->phydev, true))
-			return false;
+	if (!priv->hw_cap.eee)
+		return;
 
-		timer_setup(&priv->eee_ctrl_timer, sxgbe_eee_ctrl_timer, 0);
-		priv->eee_ctrl_timer.expires = SXGBE_LPI_TIMER(eee_timer);
+	if (phydev->enable_tx_lpi) {
 		add_timer(&priv->eee_ctrl_timer);
-
 		priv->hw->mac->set_eee_timer(priv->ioaddr,
 					     SXGBE_DEFAULT_LPI_TIMER,
-					     priv->tx_lpi_timer);
-
-		pr_info("Energy-Efficient Ethernet initialized\n");
-
-		ret = true;
+					     phydev->eee_cfg.tx_lpi_timer);
+		priv->eee_enabled = true;
+	} else {
+		sxgbe_disable_eee_mode(priv);
+		priv->eee_enabled = false;
 	}
 
-	return ret;
-}
-
-static void sxgbe_eee_adjust(const struct sxgbe_priv_data *priv)
-{
-	struct net_device *ndev = priv->dev;
-
-	/* When the EEE has been already initialised we have to
-	 * modify the PLS bit in the LPI ctrl & status reg according
-	 * to the PHY link status. For this reason.
-	 */
-	if (priv->eee_enabled)
-		priv->hw->mac->set_eee_pls(priv->ioaddr, ndev->phydev->link);
+	priv->hw->mac->set_eee_pls(priv->ioaddr, phydev->link);
 }
 
 /**
@@ -301,6 +274,16 @@ static int sxgbe_init_phy(struct net_device *ndev)
 		return -ENODEV;
 	}
 
+	if (priv->hw_cap.eee) {
+		phy_support_eee(phydev);
+		phy_eee_rx_clock_stop(priv->dev->phydev, true);
+		phydev->eee_cfg.tx_lpi_timer = SXGBE_DEFAULT_LPI_TIMER;
+
+		/* configure timer which will be used for LPI handling */
+		timer_setup(&priv->eee_ctrl_timer, sxgbe_eee_ctrl_timer, 0);
+		priv->eee_ctrl_timer.expires = SXGBE_LPI_TIMER(eee_timer);
+	}
+
 	netdev_dbg(ndev, "%s: attached to PHY (UID 0x%x) Link = %d\n",
 		   __func__, phydev->phy_id, phydev->link);
 
@@ -802,7 +785,7 @@ static void sxgbe_tx_all_clean(struct sxgbe_priv_data * const priv)
 		sxgbe_tx_queue_clean(tqueue);
 	}
 
-	if ((priv->eee_enabled) && (!priv->tx_path_in_lpi_mode)) {
+	if (priv->eee_enabled && !priv->tx_path_in_lpi_mode) {
 		sxgbe_enable_eee_mode(priv);
 		mod_timer(&priv->eee_ctrl_timer, SXGBE_LPI_TIMER(eee_timer));
 	}
@@ -1179,9 +1162,6 @@ static int sxgbe_open(struct net_device *dev)
 		priv->hw->dma->rx_watchdog(priv->ioaddr, SXGBE_MAX_DMA_RIWT);
 	}
 
-	priv->tx_lpi_timer = SXGBE_DEFAULT_LPI_TIMER;
-	priv->eee_enabled = sxgbe_eee_init(priv);
-
 	napi_enable(&priv->napi);
 	netif_start_queue(dev);
 
@@ -1207,9 +1187,6 @@ static int sxgbe_release(struct net_device *dev)
 {
 	struct sxgbe_priv_data *priv = netdev_priv(dev);
 
-	if (priv->eee_enabled)
-		del_timer_sync(&priv->eee_ctrl_timer);
-
 	/* Stop and disconnect the PHY */
 	if (dev->phydev) {
 		phy_stop(dev->phydev);
-- 
2.39.5