[PATCH net-next v10 5/9] net: phy: Represent PHY-less SFP modules with phy_port

[Maxime Chevallier <maxime.chevallier@bootlin.com>]

Now that the SFP bus infrastructure notifies when PHY-less modules are
connected, we can create a phy_port to represent it. Instead of letting
the SFP subsystem handle that, the Bus' upstream is in charge of
maintaining that phy_port and register it to the topology, as the
upstream (in this case a phy device) is directly interacting with the
underlying net_device.

Add a phy_caps helper to get the achievable modes on this module based
on what the phy_port representing the bus supports.

Signed-off-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
---
 drivers/net/phy/phy-caps.h   |   2 +
 drivers/net/phy/phy_caps.c   |  26 +++++++++
 drivers/net/phy/phy_device.c | 101 +++++++++++++++++++++++++++++++++--
 drivers/net/phy/phylink.c    |  76 ++++++++++++++++++++++++--
 include/linux/phy.h          |   6 +++
 5 files changed, 204 insertions(+), 7 deletions(-)

diff --git a/drivers/net/phy/phy-caps.h b/drivers/net/phy/phy-caps.h
index 421088e6f6e8..ec3d39a0ae06 100644
--- a/drivers/net/phy/phy-caps.h
+++ b/drivers/net/phy/phy-caps.h
@@ -66,5 +66,7 @@ void phy_caps_medium_get_supported(unsigned long *supported,
 				   enum ethtool_link_medium medium,
 				   int lanes);
 u32 phy_caps_mediums_from_linkmodes(unsigned long *linkmodes);
+void phy_caps_linkmode_filter_ifaces(unsigned long *to, const unsigned long *from,
+				     const unsigned long *interfaces);
 
 #endif /* __PHY_CAPS_H */
diff --git a/drivers/net/phy/phy_caps.c b/drivers/net/phy/phy_caps.c
index 942d43191561..558e4df4d63c 100644
--- a/drivers/net/phy/phy_caps.c
+++ b/drivers/net/phy/phy_caps.c
@@ -445,3 +445,29 @@ u32 phy_caps_mediums_from_linkmodes(unsigned long *linkmodes)
 	return mediums;
 }
 EXPORT_SYMBOL_GPL(phy_caps_mediums_from_linkmodes);
+
+/**
+ * phy_caps_linkmode_filter_ifaces() - Filter linkmodes with an interface list
+ * @to: Stores the filtered linkmodes
+ * @from: Linkmodes to filter
+ * @interfaces: Bitfield of phy_interface_t that we use for filtering
+ *
+ * Filter the provided linkmodes, only to keep the ones we can possibly achieve
+ * when using any of the provided MII interfaces.
+ */
+void phy_caps_linkmode_filter_ifaces(unsigned long *to,
+				     const unsigned long *from,
+				     const unsigned long *interfaces)
+{
+	__ETHTOOL_DECLARE_LINK_MODE_MASK(ifaces_supported) = {};
+	unsigned int ifaces_caps = 0;
+	phy_interface_t interface;
+
+	for_each_set_bit(interface, interfaces, PHY_INTERFACE_MODE_MAX)
+		ifaces_caps |= phy_caps_from_interface(interface);
+
+	phy_caps_linkmodes(ifaces_caps, ifaces_supported);
+
+	linkmode_and(to, from, ifaces_supported);
+}
+EXPORT_SYMBOL_GPL(phy_caps_linkmode_filter_ifaces);
diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c
index 301e9c365345..03bcaf5e5fe3 100644
--- a/drivers/net/phy/phy_device.c
+++ b/drivers/net/phy/phy_device.c
@@ -1490,11 +1490,21 @@ static int phy_sfp_connect_phy(void *upstream, struct phy_device *phy)
 {
 	struct phy_device *phydev = upstream;
 	struct net_device *dev = phydev->attached_dev;
+	int ret;
 
-	if (dev)
-		return phy_link_topo_add_phy(dev, phy, PHY_UPSTREAM_PHY, phydev);
+	phydev->has_sfp_mod_phy = true;
 
-	return 0;
+	/* If we aren't attached to a netdev, we can't add the SFP PHY to its
+	 * topology.
+	 */
+	if (!dev)
+		return 0;
+
+	ret = phy_link_topo_add_phy(dev, phy, PHY_UPSTREAM_PHY, phydev);
+	if (ret)
+		phydev->has_sfp_mod_phy = false;
+
+	return ret;
 }
 
 /**
@@ -1512,6 +1522,8 @@ static void phy_sfp_disconnect_phy(void *upstream, struct phy_device *phy)
 	struct phy_device *phydev = upstream;
 	struct net_device *dev = phydev->attached_dev;
 
+	phydev->has_sfp_mod_phy = false;
+
 	if (dev)
 		phy_link_topo_del_phy(dev, phy);
 }
@@ -1617,6 +1629,75 @@ static void phy_sfp_link_down(void *upstream)
 		port->ops->link_down(port);
 }
 
+static int phy_add_sfp_mod_port(struct phy_device *phydev)
+{
+	const struct sfp_module_caps *caps;
+	struct phy_port *port;
+	int ret = 0;
+
+	/* Create mod port */
+	port = phy_port_alloc();
+	if (!port)
+		return -ENOMEM;
+
+	port->active = true;
+
+	caps = sfp_get_module_caps(phydev->sfp_bus);
+
+	phy_caps_linkmode_filter_ifaces(port->supported, caps->link_modes,
+					phydev->sfp_cage_port->interfaces);
+
+	if (phydev->attached_dev) {
+		ret = phy_link_topo_add_port(phydev->attached_dev, port);
+		if (ret) {
+			phy_port_destroy(port);
+			return ret;
+		}
+	}
+
+	/* we don't use phy_add_port() here as the module port isn't a direct
+	 * interface from the PHY, but rather an extension to the sfp-bus, that
+	 * is already represented by its own phy_port
+	 */
+	phydev->mod_port = port;
+
+	return 0;
+}
+
+static void phy_del_sfp_mod_port(struct phy_device *phydev)
+{
+	if (!phydev->mod_port)
+		return;
+
+	if (phydev->attached_dev)
+		phy_link_topo_del_port(phydev->attached_dev, phydev->mod_port);
+
+	phy_port_destroy(phydev->mod_port);
+	phydev->mod_port = NULL;
+}
+
+static int phy_sfp_module_start(void *upstream)
+{
+	struct phy_device *phydev = upstream;
+
+	/* If there's a downstream SFP module, and it doesn't contain a PHY
+	 * device, let's create a phy_port to represent that module.
+	 */
+	if (!phydev->has_sfp_mod_phy)
+		return phy_add_sfp_mod_port(phydev);
+
+	return 0;
+}
+
+static void phy_sfp_module_stop(void *upstream)
+{
+	struct phy_device *phydev = upstream;
+
+	/* Called upon module removal or upstream removal */
+	if (!phydev->has_sfp_mod_phy)
+		phy_del_sfp_mod_port(phydev);
+}
+
 static const struct sfp_upstream_ops sfp_phydev_ops = {
 	.attach = phy_sfp_attach,
 	.detach = phy_sfp_detach,
@@ -1626,6 +1707,8 @@ static const struct sfp_upstream_ops sfp_phydev_ops = {
 	.link_down = phy_sfp_link_down,
 	.connect_phy = phy_sfp_connect_phy,
 	.disconnect_phy = phy_sfp_disconnect_phy,
+	.module_start = phy_sfp_module_start,
+	.module_stop = phy_sfp_module_stop,
 };
 
 static int phy_add_port(struct phy_device *phydev, struct phy_port *port)
@@ -1736,8 +1819,11 @@ static int phy_sfp_probe(struct phy_device *phydev)
 	if (ret && port) {
 		phy_del_port(phydev, port);
 		phy_port_destroy(port);
+		port = NULL;
 	}
 
+	phydev->sfp_cage_port = port;
+
 	return ret;
 }
 
@@ -1827,6 +1913,12 @@ int phy_attach_direct(struct net_device *dev, struct phy_device *phydev,
 		err = phy_link_topo_add_phy(dev, phydev, PHY_UPSTREAM_MAC, dev);
 		if (err)
 			goto error;
+
+		if (phydev->mod_port) {
+			err = phy_link_topo_add_port(dev, phydev->mod_port);
+			if (err)
+				goto error;
+		}
 	}
 
 	/* Some Ethernet drivers try to connect to a PHY device before
@@ -1960,6 +2052,8 @@ void phy_detach(struct phy_device *phydev)
 		phydev->attached_dev->phydev = NULL;
 		phydev->attached_dev = NULL;
 		phy_link_topo_del_phy(dev, phydev);
+		if (phydev->mod_port)
+			phy_link_topo_del_port(dev, phydev->mod_port);
 	}
 
 	phydev->phy_link_change = NULL;
@@ -3815,6 +3909,7 @@ static int phy_remove(struct device *dev)
 
 	sfp_bus_del_upstream(phydev->sfp_bus);
 	phydev->sfp_bus = NULL;
+	phydev->sfp_cage_port = NULL;
 
 	if (phydev->drv && phydev->drv->remove)
 		phydev->drv->remove(phydev);
diff --git a/drivers/net/phy/phylink.c b/drivers/net/phy/phylink.c
index 640b3f4f45f9..59ea3a2e5da4 100644
--- a/drivers/net/phy/phylink.c
+++ b/drivers/net/phy/phylink.c
@@ -96,6 +96,7 @@ struct phylink {
 	__ETHTOOL_DECLARE_LINK_MODE_MASK(sfp_support);
 	u8 sfp_port;
 	struct phy_port *sfp_cage_port;
+	struct phy_port *mod_port;
 
 	struct eee_config eee_cfg;
 
@@ -1790,10 +1791,15 @@ static int phylink_create_sfp_cage_port(struct phylink *pl)
 
 	ret = phy_link_topo_add_port(pl->netdev, port);
 	if (ret)
-		phy_port_destroy(port);
-	else
-		pl->sfp_cage_port = port;
+		goto out_destroy_port;
+
+	pl->sfp_cage_port = port;
+
+	return 0;
 
+out_destroy_port:
+	phy_port_destroy(port);
+	pl->sfp_cage_port = NULL;
 	return ret;
 }
 
@@ -3924,14 +3930,65 @@ static void phylink_sfp_module_remove(void *upstream)
 	phy_interface_zero(pl->sfp_interfaces);
 }
 
+static int phylink_add_sfp_mod_port(struct phylink *pl)
+{
+	const struct sfp_module_caps *caps;
+	struct phy_port *port;
+	int ret = 0;
+
+	if (!pl->sfp_cage_port)
+		return 0;
+
+	/* Create mod port */
+	port = phy_port_alloc();
+	if (!port)
+		return -ENOMEM;
+
+	port->active = true;
+
+	caps = sfp_get_module_caps(pl->sfp_bus);
+
+	phy_caps_linkmode_filter_ifaces(port->supported, caps->link_modes,
+					pl->sfp_cage_port->interfaces);
+
+	if (pl->netdev) {
+		ret = phy_link_topo_add_port(pl->netdev, port);
+		if (ret) {
+			phy_port_destroy(port);
+			return ret;
+		}
+	}
+
+	pl->mod_port = port;
+
+	return 0;
+}
+
+static void phylink_del_sfp_mod_port(struct phylink *pl)
+{
+	if (!pl->mod_port)
+		return;
+
+	if (pl->netdev)
+		phy_link_topo_del_port(pl->netdev, pl->mod_port);
+
+	phy_port_destroy(pl->mod_port);
+	pl->mod_port = NULL;
+}
+
 static int phylink_sfp_module_start(void *upstream)
 {
 	struct phylink *pl = upstream;
+	int ret;
 
 	/* If this SFP module has a PHY, start the PHY now. */
 	if (pl->phydev) {
 		phy_start(pl->phydev);
 		return 0;
+	} else {
+		ret = phylink_add_sfp_mod_port(pl);
+		if (ret)
+			return ret;
 	}
 
 	/* If the module may have a PHY but we didn't detect one we
@@ -3940,7 +3997,16 @@ static int phylink_sfp_module_start(void *upstream)
 	if (!pl->sfp_may_have_phy)
 		return 0;
 
-	return phylink_sfp_config_optical(pl);
+	ret = phylink_sfp_config_optical(pl);
+	if (ret)
+		goto del_mod_port;
+
+	return 0;
+
+del_mod_port:
+	phylink_del_sfp_mod_port(pl);
+
+	return ret;
 }
 
 static void phylink_sfp_module_stop(void *upstream)
@@ -3950,6 +4016,8 @@ static void phylink_sfp_module_stop(void *upstream)
 	/* If this SFP module has a PHY, stop it. */
 	if (pl->phydev)
 		phy_stop(pl->phydev);
+	else
+		phylink_del_sfp_mod_port(pl);
 }
 
 static void phylink_sfp_link_down(void *upstream)
diff --git a/include/linux/phy.h b/include/linux/phy.h
index 199a7aaa341b..59903257e978 100644
--- a/include/linux/phy.h
+++ b/include/linux/phy.h
@@ -582,6 +582,7 @@ struct phy_oatc14_sqi_capability {
  * @wol_enabled: Set to true if the PHY or the attached MAC have Wake-on-LAN
  * 		 enabled.
  * @is_genphy_driven: PHY is driven by one of the generic PHY drivers
+ * @has_sfp_mod_phy: Set true if downstream SFP bus's module contains a PHY
  * @state: State of the PHY for management purposes
  * @dev_flags: Device-specific flags used by the PHY driver.
  *
@@ -594,6 +595,8 @@ struct phy_oatc14_sqi_capability {
  * @phylink: Pointer to phylink instance for this PHY
  * @sfp_bus_attached: Flag indicating whether the SFP bus has been attached
  * @sfp_bus: SFP bus attached to this PHY's fiber port
+ * @sfp_cage_port: The phy_port connected to the downstream SFP cage
+ * @mod_port: phy_port representing the SFP module, if it is phy-less
  * @attached_dev: The attached enet driver's device instance ptr
  * @adjust_link: Callback for the enet controller to respond to changes: in the
  *               link state.
@@ -706,6 +709,7 @@ struct phy_device {
 	unsigned irq_rerun:1;
 
 	unsigned default_timestamp:1;
+	unsigned has_sfp_mod_phy:1;
 
 	int rate_matching;
 
@@ -785,6 +789,8 @@ struct phy_device {
 	/* This may be modified under the rtnl lock */
 	bool sfp_bus_attached;
 	struct sfp_bus *sfp_bus;
+	struct phy_port *sfp_cage_port;
+	struct phy_port *mod_port;
 	struct phylink *phylink;
 	struct net_device *attached_dev;
 	struct mii_timestamper *mii_ts;
-- 
2.54.0