net: phy: phy_port: Store information about a port's upstream

MII phy_ports are not meant to be connected directly to a link partner.
They are meant to feed into some media converter devices that will
expose an MDI phy_port, so far we only support SFP modules for that.

In the case an MDI phy_port is backed by an MII port (e.g. a SFP
module's port, backed by the SFP cage port), let's keep track of the
port id of the MII port backing it.

Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Tested-by: Aleksei Sviridkin <f@lex.la>
Reviewed-by: Christophe Leroy (CS GROUP) <chleroy@kernel.org>
Tested-by: Christophe Leroy (CS GROUP) <chleroy@kernel.org>
Signed-off-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
Link: https://patch.msgid.link/20261016133107.54054-7-maxime.chevallier@bootlin.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

2 files changed, 29 insertions, 0 deletions

diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c
index 4f897019dce2..5d4508bcfbe9 100644
--- a/drivers/net/phy/phy_device.c
+++ b/drivers/net/phy/phy_device.c
@@ -1403,6 +1403,7 @@ static int phy_sfp_connect_phy(void *upstream, struct phy_device *phy)
 	int ret;
 
 	phydev->has_sfp_mod_phy = true;
+	phy_set_upstream_port(phy, phydev->sfp_cage_port);
 
 	/* If we aren't attached to a netdev, we can't add the SFP PHY to its
 	 * topology.
@@ -1436,6 +1437,8 @@ static void phy_sfp_disconnect_phy(void *upstream, struct phy_device *phy)
 
 	if (dev)
 		phy_link_topo_del_phy(dev, phy);
+
+	phy_set_upstream_port(phy, NULL);
 }
 
 /**
@@ -1574,6 +1577,8 @@ static int phy_add_sfp_mod_port(struct phy_device *phydev)
 	 */
 	phydev->mod_port = port;
 
+	port->upstream_port = phydev->sfp_cage_port;
+
 	return 0;
 }
 
@@ -3704,6 +3709,25 @@ struct phy_port *phy_get_sfp_port(struct phy_device *phydev)
 EXPORT_SYMBOL_GPL(phy_get_sfp_port);
 
 /**
+ * phy_set_upstream_port() - Sets the phy_port controlling the MII this PHY is
+ *			     attached to.
+ * @phydev: pointer to the PHY device we set the upstream of.
+ * @port: The phy_port upstream of this PHY, can be NULL.
+ */
+void phy_set_upstream_port(struct phy_device *phydev, struct phy_port *port)
+{
+	struct phy_port *local_port;
+
+	ASSERT_RTNL();
+
+	phydev->upstream_port = port;
+
+	phy_for_each_port(phydev, local_port)
+		local_port->upstream_port = port;
+}
+EXPORT_SYMBOL_GPL(phy_set_upstream_port);
+
+/**
  * fwnode_mdio_find_device - Given a fwnode, find the mdio_device
  * @fwnode: pointer to the mdio_device's fwnode
  *
diff --git a/drivers/net/phy/phylink.c b/drivers/net/phy/phylink.c
index 667f00ddfa5e..e885da1c2831 100644
--- a/drivers/net/phy/phylink.c
+++ b/drivers/net/phy/phylink.c
@@ -4052,6 +4052,8 @@ static int phylink_add_sfp_mod_port(struct phylink *pl)
 		}
 	}
 
+	port->upstream_port = pl->sfp_cage_port;
+
 	pl->mod_port = port;
 
 	return 0;
@@ -4155,6 +4157,8 @@ static int phylink_sfp_connect_phy(void *upstream, struct phy_device *phy)
 	phy_interface_and(phy->host_interfaces, phylink_sfp_interfaces,
 			  pl->config->supported_interfaces);
 
+	phy_set_upstream_port(phy, pl->sfp_cage_port);
+
 	/* Do the initial configuration */
 	return phylink_sfp_config_phy(pl, phy);
 }
@@ -4163,6 +4167,7 @@ static void phylink_sfp_disconnect_phy(void *upstream,
 				       struct phy_device *phydev)
 {
 	phylink_disconnect_phy(upstream);
+	phy_set_upstream_port(phydev, NULL);
 }
 
 static const struct sfp_upstream_ops sfp_phylink_ops = {