mdio: Add mdio45_ethtool_spauseparam_an()

This implements the ETHTOOL_SPAUSEPARAM operation for MDIO (clause 45)
PHYs with auto-negotiation MMDs.
Signed-off-by: NBen Hutchings <bhutchings@solarflare.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/mdio.c

@@ -274,6 +274,36 @@ void mdio45_ethtool_gset_npage(const struct mdio_if_info *mdio,
 }
 EXPORT_SYMBOL(mdio45_ethtool_gset_npage);
 
+/**
+ * mdio45_ethtool_spauseparam_an - set auto-negotiated pause parameters
+ * @mdio: MDIO interface
+ * @ecmd: Ethtool request structure
+ *
+ * This function assumes that the PHY has an auto-negotiation MMD.  It
+ * will enable and disable advertising of flow control as appropriate.
+ */
+void mdio45_ethtool_spauseparam_an(const struct mdio_if_info *mdio,
+				   const struct ethtool_pauseparam *ecmd)
+{
+	int adv, old_adv;
+
+	WARN_ON(!(mdio->mmds & MDIO_DEVS_AN));
+
+	old_adv = mdio->mdio_read(mdio->dev, mdio->prtad, MDIO_MMD_AN,
+				  MDIO_AN_ADVERTISE);
+	adv = old_adv & ~(ADVERTISE_PAUSE_CAP | ADVERTISE_PAUSE_ASYM);
+	if (ecmd->autoneg)
+		adv |= mii_advertise_flowctrl(
+			(ecmd->rx_pause ? FLOW_CTRL_RX : 0) |
+			(ecmd->tx_pause ? FLOW_CTRL_TX : 0));
+	if (adv != old_adv) {
+		mdio->mdio_write(mdio->dev, mdio->prtad, MDIO_MMD_AN,
+				 MDIO_AN_ADVERTISE, adv);
+		mdio45_nway_restart(mdio);
+	}
+}
+EXPORT_SYMBOL(mdio45_ethtool_spauseparam_an);
+
 /**
  * mdio_mii_ioctl - MII ioctl interface for MDIO (clause 22 or 45) PHYs
  * @mdio: MDIO interface

include/linux/mdio.h

@@ -279,6 +279,9 @@ extern int mdio45_nway_restart(const struct mdio_if_info *mdio);
 extern void mdio45_ethtool_gset_npage(const struct mdio_if_info *mdio,
 				      struct ethtool_cmd *ecmd,
 				      u32 npage_adv, u32 npage_lpa);
+extern void
+mdio45_ethtool_spauseparam_an(const struct mdio_if_info *mdio,
+			      const struct ethtool_pauseparam *ecmd);
 
 /**
  * mdio45_ethtool_gset - get settings for ETHTOOL_GSET