Merge branch 'net: dsa: add support for phylink managed EEE'

Russell King says:

====================
net: dsa: add support for phylink managed EEE

This series adds support for phylink managed EEE to DSA, and converts
mt753x to make use of this feature.

Patch 1 implements a helper to indicate whether the MAC LPI operations
are populated (suggested by Vladimir)

Patch 2 makes the necessary changes to the core code - we retain calling
set_mac_eee(), but this method now becomes a way to merely validate the
arguments when using phylink managed EEE rather than performing any
configuration.

Patch 3 converts the mt7530 driver to use phylink managed EEE.
====================

Link: https://patch.msgid.link/Z6nWujbjxlkzK_3P@shell.armlinux.org.uk
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/dsa/mt7530.c

@@ -2957,28 +2957,61 @@ static void mt753x_phylink_mac_link_up(struct phylink_config *config,
 			mcr |= PMCR_FORCE_RX_FC_EN;
 	}
 
-	if (mode == MLO_AN_PHY && phydev && phy_init_eee(phydev, false) >= 0) {
-		switch (speed) {
-		case SPEED_1000:
-		case SPEED_2500:
-			mcr |= PMCR_FORCE_EEE1G;
-			break;
-		case SPEED_100:
-			mcr |= PMCR_FORCE_EEE100;
-			break;
-		}
-	}
-
 	mt7530_set(priv, MT753X_PMCR_P(dp->index), mcr);
 }
 
+static void mt753x_phylink_mac_disable_tx_lpi(struct phylink_config *config)
+{
+	struct dsa_port *dp = dsa_phylink_to_port(config);
+	struct mt7530_priv *priv = dp->ds->priv;
+
+	mt7530_clear(priv, MT753X_PMCR_P(dp->index),
+		     PMCR_FORCE_EEE1G | PMCR_FORCE_EEE100);
+}
+
+static int mt753x_phylink_mac_enable_tx_lpi(struct phylink_config *config,
+					    u32 timer, bool tx_clock_stop)
+{
+	struct dsa_port *dp = dsa_phylink_to_port(config);
+	struct mt7530_priv *priv = dp->ds->priv;
+	u32 val;
+
+	/* If the timer is zero, then set LPI_MODE_EN, which allows the
+	 * system to enter LPI mode immediately rather than waiting for
+	 * the LPI threshold.
+	 */
+	if (!timer)
+		val = LPI_MODE_EN;
+	else if (FIELD_FIT(LPI_THRESH_MASK, timer))
+		val = FIELD_PREP(LPI_THRESH_MASK, timer);
+	else
+		val = LPI_THRESH_MASK;
+
+	mt7530_rmw(priv, MT753X_PMEEECR_P(dp->index),
+		   LPI_THRESH_MASK | LPI_MODE_EN, val);
+
+	mt7530_set(priv, MT753X_PMCR_P(dp->index),
+		   PMCR_FORCE_EEE1G | PMCR_FORCE_EEE100);
+
+	return 0;
+}
+
 static void mt753x_phylink_get_caps(struct dsa_switch *ds, int port,
 				    struct phylink_config *config)
 {
 	struct mt7530_priv *priv = ds->priv;
+	u32 eeecr;
 
 	config->mac_capabilities = MAC_ASYM_PAUSE | MAC_SYM_PAUSE;
 
+	config->lpi_capabilities = MAC_100FD | MAC_1000FD | MAC_2500FD;
+
+	eeecr = mt7530_read(priv, MT753X_PMEEECR_P(port));
+	/* tx_lpi_timer should be in microseconds. The time units for
+	 * LPI threshold are unspecified.
+	 */
+	config->lpi_timer_default = FIELD_GET(LPI_THRESH_MASK, eeecr);
+
 	priv->info->mac_port_get_caps(ds, port, config);
 }
 
@@ -3088,18 +3121,9 @@ mt753x_setup(struct dsa_switch *ds)
 static int mt753x_set_mac_eee(struct dsa_switch *ds, int port,
 			      struct ethtool_keee *e)
 {
-	struct mt7530_priv *priv = ds->priv;
-	u32 set, mask = LPI_THRESH_MASK | LPI_MODE_EN;
-
 	if (e->tx_lpi_timer > 0xFFF)
 		return -EINVAL;
 
-	set = LPI_THRESH_SET(e->tx_lpi_timer);
-	if (!e->tx_lpi_enabled)
-		/* Force LPI Mode without a delay */
-		set |= LPI_MODE_EN;
-	mt7530_rmw(priv, MT753X_PMEEECR_P(port), mask, set);
-
 	return 0;
 }
 
@@ -3238,6 +3262,8 @@ static const struct phylink_mac_ops mt753x_phylink_mac_ops = {
 	.mac_config	= mt753x_phylink_mac_config,
 	.mac_link_down	= mt753x_phylink_mac_link_down,
 	.mac_link_up	= mt753x_phylink_mac_link_up,
+	.mac_disable_tx_lpi = mt753x_phylink_mac_disable_tx_lpi,
+	.mac_enable_tx_lpi = mt753x_phylink_mac_enable_tx_lpi,
 };
 
 const struct mt753x_info mt753x_table[] = {

drivers/net/phy/phylink.c

@@ -1957,8 +1957,7 @@ struct phylink *phylink_create(struct phylink_config *config,
 		return ERR_PTR(-EINVAL);
 	}
 
-	pl->mac_supports_eee_ops = mac_ops->mac_disable_tx_lpi &&
-				   mac_ops->mac_enable_tx_lpi;
+	pl->mac_supports_eee_ops = phylink_mac_implements_lpi(mac_ops);
 	pl->mac_supports_eee = pl->mac_supports_eee_ops &&
 			       pl->config->lpi_capabilities &&
 			       !phy_interface_empty(pl->config->lpi_interfaces);

include/linux/phylink.h

@@ -737,6 +737,18 @@ static inline int phylink_get_link_timer_ns(phy_interface_t interface)
 	}
 }
 
+/**
+ * phylink_mac_implements_lpi() - determine if MAC implements LPI ops
+ * @ops: phylink_mac_ops structure
+ *
+ * Returns true if the phylink MAC operations structure indicates that the
+ * LPI operations have been implemented, false otherwise.
+ */
+static inline bool phylink_mac_implements_lpi(const struct phylink_mac_ops *ops)
+{
+	return ops && ops->mac_disable_tx_lpi && ops->mac_enable_tx_lpi;
+}
+
 void phylink_mii_c22_pcs_decode_state(struct phylink_link_state *state,
 				      unsigned int neg_mode, u16 bmsr, u16 lpa);
 void phylink_mii_c22_pcs_get_state(struct mdio_device *pcs,

net/dsa/user.c

@@ -1243,16 +1243,25 @@ static int dsa_user_set_eee(struct net_device *dev, struct ethtool_keee *e)
 	if (!ds->ops->support_eee || !ds->ops->support_eee(ds, dp->index))
 		return -EOPNOTSUPP;
 
-	/* Port's PHY and MAC both need to be EEE capable */
-	if (!dev->phydev)
-		return -ENODEV;
+	/* If the port is using phylink managed EEE, then an unimplemented
+	 * set_mac_eee() is permissible.
+	 */
+	if (!phylink_mac_implements_lpi(ds->phylink_mac_ops)) {
+		/* Port's PHY and MAC both need to be EEE capable */
+		if (!dev->phydev)
+			return -ENODEV;
 
-	if (!ds->ops->set_mac_eee)
-		return -EOPNOTSUPP;
+		if (!ds->ops->set_mac_eee)
+			return -EOPNOTSUPP;
 
-	ret = ds->ops->set_mac_eee(ds, dp->index, e);
-	if (ret)
-		return ret;
+		ret = ds->ops->set_mac_eee(ds, dp->index, e);
+		if (ret)
+			return ret;
+	} else if (ds->ops->set_mac_eee) {
+		ret = ds->ops->set_mac_eee(ds, dp->index, e);
+		if (ret)
+			return ret;
+	}
 
 	return phylink_ethtool_set_eee(dp->pl, e);
 }