net: phy: Introduce generic SFP handling for PHY drivers

There are currently 4 PHY drivers that can drive downstream SFPs:
marvell.c, marvell10g.c, at803x.c and marvell-88x2222.c. Most of the
logic is boilerplate, either calling into generic phylib helpers (for
SFP PHY attach, bus attach, etc.) or performing the same tasks with a
bit of validation :
 - Getting the module's expected interface mode
 - Making sure the PHY supports it
 - Optionaly perform some configuration to make sure the PHY outputs
   the right mode

This can be made more generic by leveraging the phy_port, and its
configure_mii() callback which allows setting a port's interfaces when
the port is a serdes.

Introduce a generic PHY SFP support. If a driver doesn't probe the SFP
bus itself, but an SFP phandle is found in devicetree/firmware, then the
generic PHY SFP support will be used, relying on port ops.

PHY driver need to :
 - Register a .attach_port() callback
 - When a serdes port is registered to the PHY, drivers must set
   port->interfaces to the set of PHY_INTERFACE_MODE the port can output
 - If the port has limitations regarding speed, duplex and aneg, the
   port can also fine-tune the final linkmodes that can be supported
 - The port may register a set of ops, including .configure_mii(), that
   will be called at module_insert time to adjust the interface based on
   the module detected.

Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Tested-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
Link: https://patch.msgid.link/20260108080041.553250-8-maxime.chevallier@bootlin.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c
index 3fc3a30fe7ed02f83d3054c14000b5358764f611..0d9eca84081e70a843d6d86bac3da8dad8f1335a 100644 (file)
--- a/drivers/net/phy/phy_device.c
+++ b/drivers/net/phy/phy_device.c
@@ -1598,6 +1598,86 @@ void phy_sfp_detach(void *upstream, struct sfp_bus *bus)
 }
 EXPORT_SYMBOL(phy_sfp_detach);
 
+static int phy_sfp_module_insert(void *upstream, const struct sfp_eeprom_id *id)
+{
+       __ETHTOOL_DECLARE_LINK_MODE_MASK(sfp_support);
+       struct phy_device *phydev = upstream;
+       const struct sfp_module_caps *caps;
+       struct phy_port *port;
+
+       phy_interface_t iface;
+
+       linkmode_zero(sfp_support);
+
+       port = phy_get_sfp_port(phydev);
+       if (!port)
+               return -EINVAL;
+
+       caps = sfp_get_module_caps(phydev->sfp_bus);
+
+       linkmode_and(sfp_support, port->supported, caps->link_modes);
+       if (linkmode_empty(sfp_support)) {
+               dev_err(&phydev->mdio.dev, "incompatible SFP module inserted, no common linkmode\n");
+               return -EINVAL;
+       }
+
+       iface = sfp_select_interface(phydev->sfp_bus, sfp_support);
+       if (iface == PHY_INTERFACE_MODE_NA) {
+               dev_err(&phydev->mdio.dev, "PHY %s does not support the SFP module's requested MII interfaces\n",
+                       phydev_name(phydev));
+               return -EINVAL;
+       }
+
+       if (phydev->n_ports == 1)
+               phydev->port = caps->port;
+
+       if (port->ops && port->ops->configure_mii)
+               return port->ops->configure_mii(port, true, iface);
+
+       return 0;
+}
+
+static void phy_sfp_module_remove(void *upstream)
+{
+       struct phy_device *phydev = upstream;
+       struct phy_port *port = phy_get_sfp_port(phydev);
+
+       if (port && port->ops && port->ops->configure_mii)
+               port->ops->configure_mii(port, false, PHY_INTERFACE_MODE_NA);
+
+       if (phydev->n_ports == 1)
+               phydev->port = PORT_NONE;
+}
+
+static void phy_sfp_link_up(void *upstream)
+{
+       struct phy_device *phydev = upstream;
+       struct phy_port *port = phy_get_sfp_port(phydev);
+
+       if (port && port->ops && port->ops->link_up)
+               port->ops->link_up(port);
+}
+
+static void phy_sfp_link_down(void *upstream)
+{
+       struct phy_device *phydev = upstream;
+       struct phy_port *port = phy_get_sfp_port(phydev);
+
+       if (port && port->ops && port->ops->link_down)
+               port->ops->link_down(port);
+}
+
+static const struct sfp_upstream_ops sfp_phydev_ops = {
+       .attach = phy_sfp_attach,
+       .detach = phy_sfp_detach,
+       .module_insert = phy_sfp_module_insert,
+       .module_remove = phy_sfp_module_remove,
+       .link_up = phy_sfp_link_up,
+       .link_down = phy_sfp_link_down,
+       .connect_phy = phy_sfp_connect_phy,
+       .disconnect_phy = phy_sfp_disconnect_phy,
+};
+
 static int phy_add_port(struct phy_device *phydev, struct phy_port *port)
 {
        int ret = 0;
@@ -1658,6 +1738,7 @@ static int phy_setup_sfp_port(struct phy_device *phydev)
         * is a MII port.
         */
        port->is_mii = true;
+       port->is_sfp = true;
 
        /* The port->supported and port->interfaces list will be populated
         * when attaching the port to the phydev.
@@ -3505,6 +3586,13 @@ static int phy_setup_ports(struct phy_device *phydev)
        if (ret)
                return ret;
 
+       /* Use generic SFP probing only if the driver didn't do so already */
+       if (!phydev->sfp_bus) {
+               ret = phy_sfp_probe(phydev, &sfp_phydev_ops);
+               if (ret)
+                       goto out;
+       }
+
        if (phydev->n_ports < phydev->max_n_ports) {
                ret = phy_default_setup_single_port(phydev);
                if (ret)
@@ -3540,6 +3628,25 @@ out:
        return ret;
 }
 
+/**
+ * phy_get_sfp_port() - Returns the first valid SFP port of a PHY
+ * @phydev: pointer to the PHY device to get the SFP port from
+ *
+ * Returns: The first active SFP (serdes) port of a PHY device, NULL if none
+ * exist.
+ */
+struct phy_port *phy_get_sfp_port(struct phy_device *phydev)
+{
+       struct phy_port *port;
+
+       list_for_each_entry(port, &phydev->ports, head)
+               if (port->active && port->is_sfp)
+                       return port;
+
+       return NULL;
+}
+EXPORT_SYMBOL_GPL(phy_get_sfp_port);
+
 /**
  * fwnode_mdio_find_device - Given a fwnode, find the mdio_device
  * @fwnode: pointer to the mdio_device's fwnode

diff --git a/include/linux/phy.h b/include/linux/phy.h
index b7e769b52e6c1db79dcac11c800b706d8fe64add..eb7fd533b0e44891f510aac9d5abdd5531e69e34 100644 (file)
--- a/include/linux/phy.h
+++ b/include/linux/phy.h
@@ -2455,6 +2455,8 @@ int __phy_hwtstamp_set(struct phy_device *phydev,
                       struct kernel_hwtstamp_config *config,
                       struct netlink_ext_ack *extack);
 
+struct phy_port *phy_get_sfp_port(struct phy_device *phydev);
+
 extern const struct bus_type mdio_bus_type;
 extern const struct class mdio_bus_class;
 

diff --git a/include/linux/phy_port.h b/include/linux/phy_port.h
index ce0208fbccf70ed99248771af6e65efd157f1106..550c3f4ab19f33fb07411b08ea14ffbb6a762431 100644 (file)
--- a/include/linux/phy_port.h
+++ b/include/linux/phy_port.h
@@ -49,6 +49,7 @@ struct phy_port_ops {
  * @active: Indicates if the port is currently part of the active link.
  * @is_mii: Indicates if this port is MII (Media Independent Interface),
  *          or MDI (Media Dependent Interface).
+ * @is_sfp: Indicates if this port drives an SFP cage.
  */
 struct phy_port {
        struct list_head head;
@@ -67,6 +68,7 @@ struct phy_port {
        unsigned int not_described:1;
        unsigned int active:1;
        unsigned int is_mii:1;
+       unsigned int is_sfp:1;
 };
 
 struct phy_port *phy_port_alloc(void);