net: phy: phy_port: Correctly recompute the port's linkmodes

a PHY-driven phy_port contains a 'supported' field containing the
linkmodes available on this port. This is populated based on :
 - The PHY's reported features
 - The DT representation of the connector
 - The PHY's attach_mdi() callback

As these different attrbution methods work in conjunction, the helper
phy_port_update_supported() recomputes the final 'supported' value based
on the populated mediums, linkmodes and pairs.

However this recompute wasn't correctly implemented, and added more
modes than necessary by or'ing the medium-specific modes to the existing
support. Let's fix this and properly filter the modes.

Fixes: 589e934d2735 ("net: phy: Introduce PHY ports representation")
Signed-off-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
Reviewed-by: Christophe Leroy (CS GROUP) <chleroy@kernel.org>
Link: https://patch.msgid.link/20260205092317.755906-4-maxime.chevallier@bootlin.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/drivers/net/phy/phy_port.c b/drivers/net/phy/phy_port.c
index a269e9ea12c43fbe46bd14ae6b7ad2b006945214..63d1bb154dc75c27ef43c1f969ae64e781bda3cf 100644 (file)
--- a/drivers/net/phy/phy_port.c
+++ b/drivers/net/phy/phy_port.c
@@ -108,16 +108,10 @@ EXPORT_SYMBOL_GPL(phy_of_parse_port);
  */
 void phy_port_update_supported(struct phy_port *port)
 {
-       __ETHTOOL_DECLARE_LINK_MODE_MASK(supported) = { 0 };
+       __ETHTOOL_DECLARE_LINK_MODE_MASK(supported) = {0};
        unsigned long mode;
        int i;
 
-       for_each_set_bit(i, &port->mediums, __ETHTOOL_LINK_MEDIUM_LAST) {
-               linkmode_zero(supported);
-               phy_caps_medium_get_supported(supported, i, port->pairs);
-               linkmode_or(port->supported, port->supported, supported);
-       }
-
        /* If there's no pairs specified, we grab the default number of
         * pairs as the max of the default pairs for each linkmode
         */
@@ -127,6 +121,22 @@ void phy_port_update_supported(struct phy_port *port)
                        port->pairs = max_t(int, port->pairs,
                                            ethtool_linkmode_n_pairs(mode));
 
+       for_each_set_bit(i, &port->mediums, __ETHTOOL_LINK_MEDIUM_LAST) {
+               __ETHTOOL_DECLARE_LINK_MODE_MASK(med_supported) = {0};
+
+               phy_caps_medium_get_supported(med_supported, i, port->pairs);
+               linkmode_or(supported, supported, med_supported);
+       }
+
+       /* If port->supported is already populated, filter it out with the
+        * medium/pair support. Otherwise, let's just use this medium-based
+        * support as the port's supported list.
+        */
+       if (linkmode_empty(port->supported))
+               linkmode_copy(port->supported, supported);
+       else
+               linkmode_and(port->supported, supported, port->supported);
+
        /* Serdes ports supported through SFP may not have any medium set,
         * as they will output PHY_INTERFACE_MODE_XXX modes. In that case, derive
         * the supported list based on these interfaces