Merge branch 'net-phy-introduce-phy-ports-representation'

Maxime Chevallier says:

====================
net: phy: Introduce PHY ports representation

A few important notes:

 - This is only a first phase. It instantiates the port, and leverage
   that to make the MAC <-> PHY <-> SFP usecase simpler.

 - Next phase will deal with controlling the port state, as well as the
   netlink uAPI for that.

 - The end-goal is to enable support for complex port MUX. This
   preliminary work focuses on PHY-driven ports, but this will be
   extended to support muxing at the MII level (Multi-phy, or compo PHY
   + SFP as found on Turris Omnia for example).

 - The naming is definitely not set in stone. I named that "phy_port",
   but this may convey the false sense that this is phylib-specific.
   Even the word "port" is not that great, as it already has several
   different meanings in the net world (switch port, devlink port,
   etc.). I used the term "connector" in the binding.

A bit of history on that work :

The end goal that I personnaly want to achieve is :

            + PHY - RJ45
            |
 MAC - MUX -+ PHY - RJ45

After many discussions here on netdev@, but also at netdevconf[1] and
LPC[2], there appears to be several analoguous designs that exist out
there.

[1] : https://netdevconf.info/0x17/sessions/talk/improving-multi-phy-and-multi-port-interfaces.html
[2] : https://lpc.events/event/18/contributions/1964/ (video isn't the
right one)

Take the MAchiatobin, it has 2 interfaces that looks like this :

 MAC - PHY -+ RJ45
            |
	    + SFP - Whatever the module does

Now, looking at the Turris Omnia, we have :

 MAC - MUX -+ PHY - RJ45
            |
	    + SFP - Whatever the module does

We can find more example of this kind of designs, the common part is
that we expose multiple front-facing media ports. This is what this
current work aims at supporting. As of right now, it does'nt add any
support for muxing, but this will come later on.

This first phase focuses on phy-driven ports only, but there are already
quite some challenges already. For one, we can't really autodetect how
many ports are sitting behind a PHY. That's why this series introduces a
new binding. Describing ports in DT should however be a last-resort
thing when we need to clear some ambiguity about the PHY media-side.

The only use-cases that we have today for multi-port PHYs are combo PHYs
that drive both a Copper port and an SFP (the Macchiatobin case). This
in itself is challenging and this series only addresses part of this
support, by registering a phy_port for the PHY <-> SFP connection. The
SFP module should in the end be considered as a port as well, but that's
not yet the case.

However, because now PHYs can register phy_ports for every media-side
interface they have, they can register the capabilities of their ports,
which allows making the PHY-driver SFP case much more generic.
====================

Link: https://patch.msgid.link/20260108080041.553250-1-maxime.chevallier@bootlin.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

3 files changed, 189 insertions, 9 deletions

diff --git a/include/linux/ethtool.h b/include/linux/ethtool.h
index 5c9162193d26..798abec67a1b 100644
--- a/include/linux/ethtool.h
+++ b/include/linux/ethtool.h
@@ -216,13 +216,43 @@ static inline u8 *ethtool_rxfh_context_key(struct ethtool_rxfh_context *ctx)
 void ethtool_rxfh_context_lost(struct net_device *dev, u32 context_id);
 
 struct link_mode_info {
-	int                             speed;
-	u8                              lanes;
-	u8                              duplex;
+	int	speed;
+	u8	lanes;
+	u8	min_pairs;
+	u8	pairs;
+	u8	duplex;
+	u16	mediums;
 };
 
 extern const struct link_mode_info link_mode_params[];
 
+enum ethtool_link_medium {
+	ETHTOOL_LINK_MEDIUM_BASET = 0,
+	ETHTOOL_LINK_MEDIUM_BASEK,
+	ETHTOOL_LINK_MEDIUM_BASES,
+	ETHTOOL_LINK_MEDIUM_BASEC,
+	ETHTOOL_LINK_MEDIUM_BASEL,
+	ETHTOOL_LINK_MEDIUM_BASED,
+	ETHTOOL_LINK_MEDIUM_BASEE,
+	ETHTOOL_LINK_MEDIUM_BASEF,
+	ETHTOOL_LINK_MEDIUM_BASEV,
+	ETHTOOL_LINK_MEDIUM_BASEMLD,
+	ETHTOOL_LINK_MEDIUM_NONE,
+
+	__ETHTOOL_LINK_MEDIUM_LAST,
+};
+
+#define ETHTOOL_MEDIUM_FIBER_BITS (BIT(ETHTOOL_LINK_MEDIUM_BASES) | \
+				   BIT(ETHTOOL_LINK_MEDIUM_BASEL) | \
+				   BIT(ETHTOOL_LINK_MEDIUM_BASEF))
+
+enum ethtool_link_medium ethtool_str_to_medium(const char *str);
+
+static inline int ethtool_linkmode_n_pairs(unsigned int mode)
+{
+	return link_mode_params[mode].pairs;
+}
+
 /* declare a link mode bitmap */
 #define __ETHTOOL_DECLARE_LINK_MODE_MASK(name)		\
 	DECLARE_BITMAP(name, __ETHTOOL_LINK_MODE_MASK_NBITS)
diff --git a/include/linux/phy.h b/include/linux/phy.h
index fbbe028cc4b7..3beb5dbba791 100644
--- a/include/linux/phy.h
+++ b/include/linux/phy.h
@@ -327,6 +327,7 @@ static inline long rgmii_clock(int speed)
 struct device;
 struct kernel_hwtstamp_config;
 struct phylink;
+struct phy_port;
 struct sfp_bus;
 struct sfp_upstream_ops;
 struct sk_buff;
@@ -645,6 +646,9 @@ struct phy_oatc14_sqi_capability {
  * @master_slave_state: Current master/slave configuration
  * @mii_ts: Pointer to time stamper callbacks
  * @psec: Pointer to Power Sourcing Equipment control struct
+ * @ports: List of PHY ports structures
+ * @n_ports: Number of ports currently attached to the PHY
+ * @max_n_ports: Max number of ports this PHY can expose
  * @lock:  Mutex for serialization access to PHY
  * @state_queue: Work queue for state machine
  * @link_down_events: Number of times link was lost
@@ -783,6 +787,10 @@ struct phy_device {
 	struct mii_timestamper *mii_ts;
 	struct pse_control *psec;
 
+	struct list_head ports;
+	int n_ports;
+	int max_n_ports;
+
 	u8 mdix;
 	u8 mdix_ctrl;
 
@@ -807,6 +815,9 @@ struct phy_device {
 
 #define to_phy_device(__dev)	container_of_const(to_mdio_device(__dev), struct phy_device, mdio)
 
+#define phy_for_each_port(phydev, port) \
+	list_for_each_entry(port, &(phydev)->ports, head)
+
 /**
  * struct phy_tdr_config - Configuration of a TDR raw test
  *
@@ -1507,6 +1518,49 @@ struct phy_driver {
 	 * Returns the time in jiffies until the next update event.
 	 */
 	unsigned int (*get_next_update_time)(struct phy_device *dev);
+
+	/**
+	 * @attach_mii_port: Attach the given MII port to the PHY device
+	 * @dev: PHY device to notify
+	 * @port: The port being added
+	 *
+	 * Called when an MII port that needs to be driven by the PHY is found.
+	 *
+	 * The port that is being passed may or may not be initialized. If it is
+	 * already initialized, it is by the generic port representation from
+	 * devicetree, which superseeds any strapping or vendor-specific
+	 * properties.
+	 *
+	 * If the port isn't initialized, the port->mediums and port->lanes
+	 * fields must be set, possibly according to strapping information.
+	 *
+	 * The PHY driver must set the port->interfaces field to indicate the
+	 * possible MII modes that this PHY can output on the port.
+	 *
+	 * Returns 0, or an error code.
+	 */
+	int (*attach_mii_port)(struct phy_device *dev, struct phy_port *port);
+
+	/**
+	 * @attach_mdi_port: Attach the given MII port to the PHY device
+	 * @dev: PHY device to notify
+	 * @port: The port being added
+	 *
+	 * Called when a port that needs to be driven by the PHY is found. The
+	 * number of time this will be called depends on phydev->max_n_ports,
+	 * which the driver can change in .probe().
+	 *
+	 * The port that is being passed may or may not be initialized. If it is
+	 * already initialized, it is by the generic port representation from
+	 * devicetree, which superseeds any strapping or vendor-specific
+	 * properties.
+	 *
+	 * If the port isn't initialized, the port->mediums and port->lanes
+	 * fields must be set, possibly according to strapping information.
+	 *
+	 * Returns 0, or an error code.
+	 */
+	int (*attach_mdi_port)(struct phy_device *dev, struct phy_port *port);
 };
 #define to_phy_driver(d) container_of_const(to_mdio_common_driver(d),		\
 				      struct phy_driver, mdiodrv)
@@ -2097,12 +2151,6 @@ int phy_suspend(struct phy_device *phydev);
 int phy_resume(struct phy_device *phydev);
 int __phy_resume(struct phy_device *phydev);
 int phy_loopback(struct phy_device *phydev, bool enable, int speed);
-int phy_sfp_connect_phy(void *upstream, struct phy_device *phy);
-void phy_sfp_disconnect_phy(void *upstream, struct phy_device *phy);
-void phy_sfp_attach(void *upstream, struct sfp_bus *bus);
-void phy_sfp_detach(void *upstream, struct sfp_bus *bus);
-int phy_sfp_probe(struct phy_device *phydev,
-	          const struct sfp_upstream_ops *ops);
 struct phy_device *phy_attach(struct net_device *dev, const char *bus_id,
 			      phy_interface_t interface);
 struct phy_device *phy_find_next(struct mii_bus *bus, struct phy_device *pos);
@@ -2310,6 +2358,7 @@ void phy_trigger_machine(struct phy_device *phydev);
 void phy_mac_interrupt(struct phy_device *phydev);
 void phy_start_machine(struct phy_device *phydev);
 void phy_stop_machine(struct phy_device *phydev);
+
 void phy_ethtool_ksettings_get(struct phy_device *phydev,
 			       struct ethtool_link_ksettings *cmd);
 int phy_ethtool_ksettings_set(struct phy_device *phydev,
@@ -2400,6 +2449,8 @@ 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
new file mode 100644
index 000000000000..0ef0f5ce4709
--- /dev/null
+++ b/include/linux/phy_port.h
@@ -0,0 +1,99 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+#ifndef __PHY_PORT_H
+#define __PHY_PORT_H
+
+#include <linux/ethtool.h>
+#include <linux/types.h>
+#include <linux/phy.h>
+
+struct phy_port;
+
+/**
+ * enum phy_port_parent - The device this port is attached to
+ *
+ * @PHY_PORT_PHY: Indicates that the port is driven by a PHY device
+ */
+enum phy_port_parent {
+	PHY_PORT_PHY,
+};
+
+struct phy_port_ops {
+	/* Sometimes, the link state can be retrieved from physical,
+	 * out-of-band channels such as the LOS signal on SFP. These
+	 * callbacks allows notifying the port about state changes
+	 */
+	void (*link_up)(struct phy_port *port);
+	void (*link_down)(struct phy_port *port);
+
+	/* If the port acts as a Media Independent Interface (Serdes port),
+	 * configures the port with the relevant state and mode. When enable is
+	 * not set, interface should be ignored
+	 */
+	int (*configure_mii)(struct phy_port *port, bool enable, phy_interface_t interface);
+};
+
+/**
+ * struct phy_port - A representation of a network device physical interface
+ *
+ * @head: Used by the port's parent to list ports
+ * @parent_type: The type of device this port is directly connected to
+ * @phy: If the parent is PHY_PORT_PHYDEV, the PHY controlling that port
+ * @ops: Callback ops implemented by the port controller
+ * @pairs: The number of  pairs this port has, 0 if not applicable
+ * @mediums: Bitmask of the physical mediums this port provides access to
+ * @supported: The link modes this port can expose, if this port is MDI (not MII)
+ * @interfaces: The MII interfaces this port supports, if this port is MII
+ * @not_described: Indicates to the parent driver if this port isn't described,
+ *		   so it's up to the parent to filter its capabilities.
+ * @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;
+	enum phy_port_parent parent_type;
+	union {
+		struct phy_device *phy;
+	};
+
+	const struct phy_port_ops *ops;
+
+	int pairs;
+	unsigned long mediums;
+	__ETHTOOL_DECLARE_LINK_MODE_MASK(supported);
+	DECLARE_PHY_INTERFACE_MASK(interfaces);
+
+	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);
+void phy_port_destroy(struct phy_port *port);
+
+static inline struct phy_device *port_phydev(struct phy_port *port)
+{
+	return port->phy;
+}
+
+struct phy_port *phy_of_parse_port(struct device_node *dn);
+
+static inline bool phy_port_is_copper(struct phy_port *port)
+{
+	return port->mediums == BIT(ETHTOOL_LINK_MEDIUM_BASET);
+}
+
+static inline bool phy_port_is_fiber(struct phy_port *port)
+{
+	return !!(port->mediums & ETHTOOL_MEDIUM_FIBER_BITS);
+}
+
+void phy_port_update_supported(struct phy_port *port);
+int phy_port_restrict_mediums(struct phy_port *port, unsigned long mediums);
+
+int phy_port_get_type(struct phy_port *port);
+
+#endif