Merge branch 'phy-listing-and-topology-tracking'

Maxime Chevallier says:

====================
Introduce PHY listing and link_topology tracking

This is V18 of the phy_link_topology series, aiming at improving support
for multiple PHYs being attached to the same MAC.

V18 is a simple rebase of the V17 on top of net-next, gathering the
tested-by and reviewed-by tags from Christophe (thanks !).

This iteration is also one patch shorter than V17 (patch 12/14 in V17 is gone),
as one of the patches used to fix an issue that has now been resolved by
Simon Horman in

743ff02152bc ethtool: Don't check for NULL info in prepare_data callbacks

As a remainder, here's what the PHY listings would look like :
 - eth0 has a 88x3310 acting as media converter, and an SFP module with
   an embedded 88e1111 PHY
 - eth2 has a 88e1510 PHY

PHY for eth0:
PHY index: 1
Driver name: mv88x3310
PHY device name: f212a600.mdio-mii:00
Downstream SFP bus name: sfp-eth0
Upstream type: MAC

PHY for eth0:
PHY index: 2
Driver name: Marvell 88E1111
PHY device name: i2c:sfp-eth0:16
Upstream type: PHY
Upstream PHY index: 1
Upstream SFP name: sfp-eth0

PHY for eth2:
PHY index: 1
Driver name: Marvell 88E1510
PHY device name: f212a200.mdio-mii:00
Upstream type: MAC

Ethtool patches : https://github.com/minimaxwell/ethtool/tree/mc/topo-v16
(this branch is compatible with this V18 series)

Link to V17: https://lore.kernel.org/netdev/20240709063039.2909536-1-maxime.chevallier@bootlin.com/
Link to V16: https://lore.kernel.org/netdev/20240705132706.13588-1-maxime.chevallier@bootlin.com/
Link to V15: https://lore.kernel.org/netdev/20240703140806.271938-1-maxime.chevallier@bootlin.com/
Link to V14: https://lore.kernel.org/netdev/20240701131801.1227740-1-maxime.chevallier@bootlin.com/
Link to V13: https://lore.kernel.org/netdev/20240607071836.911403-1-maxime.chevallier@bootlin.com/
Link to v12: https://lore.kernel.org/netdev/20240605124920.720690-1-maxime.chevallier@bootlin.com/
Link to v11: https://lore.kernel.org/netdev/20240404093004.2552221-1-maxime.chevallier@bootlin.com/
Link to V10: https://lore.kernel.org/netdev/20240304151011.1610175-1-maxime.chevallier@bootlin.com/
Link to V9: https://lore.kernel.org/netdev/20240228114728.51861-1-maxime.chevallier@bootlin.com/
Link to V8: https://lore.kernel.org/netdev/20240220184217.3689988-1-maxime.chevallier@bootlin.com/
Link to V7: https://lore.kernel.org/netdev/20240213150431.1796171-1-maxime.chevallier@bootlin.com/
Link to V6: https://lore.kernel.org/netdev/20240126183851.2081418-1-maxime.chevallier@bootlin.com/
Link to V5: https://lore.kernel.org/netdev/20231221180047.1924733-1-maxime.chevallier@bootlin.com/
Link to V4: https://lore.kernel.org/netdev/20231215171237.1152563-1-maxime.chevallier@bootlin.com/
Link to V3: https://lore.kernel.org/netdev/20231201163704.1306431-1-maxime.chevallier@bootlin.com/
Link to V2: https://lore.kernel.org/netdev/20231117162323.626979-1-maxime.chevallier@bootlin.com/
Link to V1: https://lore.kernel.org/netdev/20230907092407.647139-1-maxime.chevallier@bootlin.com/

More discussions on specific issues that happened in 6.9-rc:

https://lore.kernel.org/netdev/20240412104615.3779632-1-maxime.chevallier@bootlin.com/
https://lore.kernel.org/netdev/20240429131008.439231-1-maxime.chevallier@bootlin.com/
https://lore.kernel.org/netdev/20240507102822.2023826-1-maxime.chevallier@bootlin.com/
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

10 files changed, 190 insertions, 4 deletions

diff --git a/drivers/net/phy/Makefile b/drivers/net/phy/Makefile
index f086a606a87e..33adb3df5f64 100644
--- a/drivers/net/phy/Makefile
+++ b/drivers/net/phy/Makefile
@@ -2,7 +2,7 @@
 # Makefile for Linux PHY drivers
 
 libphy-y			:= phy.o phy-c45.o phy-core.o phy_device.o \
-				   linkmode.o
+				   linkmode.o phy_link_topology.o
 mdio-bus-y			+= mdio_bus.o mdio_device.o
 
 ifdef CONFIG_MDIO_DEVICE
diff --git a/drivers/net/phy/marvell-88x2222.c b/drivers/net/phy/marvell-88x2222.c
index b88398e6872b..0b777cdd7078 100644
--- a/drivers/net/phy/marvell-88x2222.c
+++ b/drivers/net/phy/marvell-88x2222.c
@@ -553,6 +553,8 @@ static const struct sfp_upstream_ops sfp_phy_ops = {
 	.link_down = mv2222_sfp_link_down,
 	.attach = phy_sfp_attach,
 	.detach = phy_sfp_detach,
+	.connect_phy = phy_sfp_connect_phy,
+	.disconnect_phy = phy_sfp_disconnect_phy,
 };
 
 static int mv2222_probe(struct phy_device *phydev)
diff --git a/drivers/net/phy/marvell.c b/drivers/net/phy/marvell.c
index b89fbffa6a93..9964bf3dea2f 100644
--- a/drivers/net/phy/marvell.c
+++ b/drivers/net/phy/marvell.c
@@ -3613,6 +3613,8 @@ static const struct sfp_upstream_ops m88e1510_sfp_ops = {
 	.module_remove = m88e1510_sfp_remove,
 	.attach = phy_sfp_attach,
 	.detach = phy_sfp_detach,
+	.connect_phy = phy_sfp_connect_phy,
+	.disconnect_phy = phy_sfp_disconnect_phy,
 };
 
 static int m88e1510_probe(struct phy_device *phydev)
diff --git a/drivers/net/phy/marvell10g.c b/drivers/net/phy/marvell10g.c
index ad43e280930c..6642eb642d4b 100644
--- a/drivers/net/phy/marvell10g.c
+++ b/drivers/net/phy/marvell10g.c
@@ -503,6 +503,8 @@ static int mv3310_sfp_insert(void *upstream, const struct sfp_eeprom_id *id)
 static const struct sfp_upstream_ops mv3310_sfp_ops = {
 	.attach = phy_sfp_attach,
 	.detach = phy_sfp_detach,
+	.connect_phy = phy_sfp_connect_phy,
+	.disconnect_phy = phy_sfp_disconnect_phy,
 	.module_insert = mv3310_sfp_insert,
 };
 
diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c
index 159e71c1c972..8f5314c1fecc 100644
--- a/drivers/net/phy/phy_device.c
+++ b/drivers/net/phy/phy_device.c
@@ -29,6 +29,7 @@
 #include <linux/phy.h>
 #include <linux/phylib_stubs.h>
 #include <linux/phy_led_triggers.h>
+#include <linux/phy_link_topology.h>
 #include <linux/pse-pd/pse.h>
 #include <linux/property.h>
 #include <linux/rtnetlink.h>
@@ -1385,6 +1386,48 @@ phy_standalone_show(struct device *dev, struct device_attribute *attr,
 static DEVICE_ATTR_RO(phy_standalone);
 
 /**
+ * phy_sfp_connect_phy - Connect the SFP module's PHY to the upstream PHY
+ * @upstream: pointer to the upstream phy device
+ * @phy: pointer to the SFP module's phy device
+ *
+ * This helper allows keeping track of PHY devices on the link. It adds the
+ * SFP module's phy to the phy namespace of the upstream phy
+ *
+ * Return: 0 on success, otherwise a negative error code.
+ */
+int phy_sfp_connect_phy(void *upstream, struct phy_device *phy)
+{
+	struct phy_device *phydev = upstream;
+	struct net_device *dev = phydev->attached_dev;
+
+	if (dev)
+		return phy_link_topo_add_phy(dev, phy, PHY_UPSTREAM_PHY, phydev);
+
+	return 0;
+}
+EXPORT_SYMBOL(phy_sfp_connect_phy);
+
+/**
+ * phy_sfp_disconnect_phy - Disconnect the SFP module's PHY from the upstream PHY
+ * @upstream: pointer to the upstream phy device
+ * @phy: pointer to the SFP module's phy device
+ *
+ * This helper allows keeping track of PHY devices on the link. It removes the
+ * SFP module's phy to the phy namespace of the upstream phy. As the module phy
+ * will be destroyed, re-inserting the same module will add a new phy with a
+ * new index.
+ */
+void phy_sfp_disconnect_phy(void *upstream, struct phy_device *phy)
+{
+	struct phy_device *phydev = upstream;
+	struct net_device *dev = phydev->attached_dev;
+
+	if (dev)
+		phy_link_topo_del_phy(dev, phy);
+}
+EXPORT_SYMBOL(phy_sfp_disconnect_phy);
+
+/**
  * phy_sfp_attach - attach the SFP bus to the PHY upstream network device
  * @upstream: pointer to the phy device
  * @bus: sfp bus representing cage being attached
@@ -1526,6 +1569,10 @@ int phy_attach_direct(struct net_device *dev, struct phy_device *phydev,
 
 		if (phydev->sfp_bus_attached)
 			dev->sfp_bus = phydev->sfp_bus;
+
+		err = phy_link_topo_add_phy(dev, phydev, PHY_UPSTREAM_MAC, dev);
+		if (err)
+			goto error;
 	}
 
 	/* Some Ethernet drivers try to connect to a PHY device before
@@ -1953,6 +2000,7 @@ void phy_detach(struct phy_device *phydev)
 	if (dev) {
 		phydev->attached_dev->phydev = NULL;
 		phydev->attached_dev = NULL;
+		phy_link_topo_del_phy(dev, phydev);
 	}
 	phydev->phylink = NULL;
 
diff --git a/drivers/net/phy/phy_link_topology.c b/drivers/net/phy/phy_link_topology.c
new file mode 100644
index 000000000000..4a5d73002a1a
--- /dev/null
+++ b/drivers/net/phy/phy_link_topology.c
@@ -0,0 +1,105 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Infrastructure to handle all PHY devices connected to a given netdev,
+ * either directly or indirectly attached.
+ *
+ * Copyright (c) 2023 Maxime Chevallier<maxime.chevallier@bootlin.com>
+ */
+
+#include <linux/phy_link_topology.h>
+#include <linux/phy.h>
+#include <linux/rtnetlink.h>
+#include <linux/xarray.h>
+
+static int netdev_alloc_phy_link_topology(struct net_device *dev)
+{
+	struct phy_link_topology *topo;
+
+	topo = kzalloc(sizeof(*topo), GFP_KERNEL);
+	if (!topo)
+		return -ENOMEM;
+
+	xa_init_flags(&topo->phys, XA_FLAGS_ALLOC1);
+	topo->next_phy_index = 1;
+
+	dev->link_topo = topo;
+
+	return 0;
+}
+
+int phy_link_topo_add_phy(struct net_device *dev,
+			  struct phy_device *phy,
+			  enum phy_upstream upt, void *upstream)
+{
+	struct phy_link_topology *topo = dev->link_topo;
+	struct phy_device_node *pdn;
+	int ret;
+
+	if (!topo) {
+		ret = netdev_alloc_phy_link_topology(dev);
+		if (ret)
+			return ret;
+
+		topo = dev->link_topo;
+	}
+
+	pdn = kzalloc(sizeof(*pdn), GFP_KERNEL);
+	if (!pdn)
+		return -ENOMEM;
+
+	pdn->phy = phy;
+	switch (upt) {
+	case PHY_UPSTREAM_MAC:
+		pdn->upstream.netdev = (struct net_device *)upstream;
+		if (phy_on_sfp(phy))
+			pdn->parent_sfp_bus = pdn->upstream.netdev->sfp_bus;
+		break;
+	case PHY_UPSTREAM_PHY:
+		pdn->upstream.phydev = (struct phy_device *)upstream;
+		if (phy_on_sfp(phy))
+			pdn->parent_sfp_bus = pdn->upstream.phydev->sfp_bus;
+		break;
+	default:
+		ret = -EINVAL;
+		goto err;
+	}
+	pdn->upstream_type = upt;
+
+	/* Attempt to re-use a previously allocated phy_index */
+	if (phy->phyindex)
+		ret = xa_insert(&topo->phys, phy->phyindex, pdn, GFP_KERNEL);
+	else
+		ret = xa_alloc_cyclic(&topo->phys, &phy->phyindex, pdn,
+				      xa_limit_32b, &topo->next_phy_index,
+				      GFP_KERNEL);
+
+	if (ret)
+		goto err;
+
+	return 0;
+
+err:
+	kfree(pdn);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(phy_link_topo_add_phy);
+
+void phy_link_topo_del_phy(struct net_device *dev,
+			   struct phy_device *phy)
+{
+	struct phy_link_topology *topo = dev->link_topo;
+	struct phy_device_node *pdn;
+
+	if (!topo)
+		return;
+
+	pdn = xa_erase(&topo->phys, phy->phyindex);
+
+	/* We delete the PHY from the topology, however we don't re-set the
+	 * phy->phyindex field. If the PHY isn't gone, we can re-assign it the
+	 * same index next time it's added back to the topology
+	 */
+
+	kfree(pdn);
+}
+EXPORT_SYMBOL_GPL(phy_link_topo_del_phy);
diff --git a/drivers/net/phy/phylink.c b/drivers/net/phy/phylink.c
index 51c526d227fa..ab4e9fc03017 100644
--- a/drivers/net/phy/phylink.c
+++ b/drivers/net/phy/phylink.c
@@ -3423,7 +3423,8 @@ static int phylink_sfp_connect_phy(void *upstream, struct phy_device *phy)
 	return ret;
 }
 
-static void phylink_sfp_disconnect_phy(void *upstream)
+static void phylink_sfp_disconnect_phy(void *upstream,
+				       struct phy_device *phydev)
 {
 	phylink_disconnect_phy(upstream);
 }
diff --git a/drivers/net/phy/qcom/at803x.c b/drivers/net/phy/qcom/at803x.c
index c8f83e5f78ab..105602581a03 100644
--- a/drivers/net/phy/qcom/at803x.c
+++ b/drivers/net/phy/qcom/at803x.c
@@ -770,6 +770,8 @@ static const struct sfp_upstream_ops at8031_sfp_ops = {
 	.attach = phy_sfp_attach,
 	.detach = phy_sfp_detach,
 	.module_insert = at8031_sfp_insert,
+	.connect_phy = phy_sfp_connect_phy,
+	.disconnect_phy = phy_sfp_disconnect_phy,
 };
 
 static int at8031_parse_dt(struct phy_device *phydev)
diff --git a/drivers/net/phy/qcom/qca807x.c b/drivers/net/phy/qcom/qca807x.c
index ba558486c72f..bd8a51ec0ecd 100644
--- a/drivers/net/phy/qcom/qca807x.c
+++ b/drivers/net/phy/qcom/qca807x.c
@@ -699,6 +699,8 @@ static const struct sfp_upstream_ops qca807x_sfp_ops = {
 	.detach = phy_sfp_detach,
 	.module_insert = qca807x_sfp_insert,
 	.module_remove = qca807x_sfp_remove,
+	.connect_phy = phy_sfp_connect_phy,
+	.disconnect_phy = phy_sfp_disconnect_phy,
 };
 
 static int qca807x_probe(struct phy_device *phydev)
diff --git a/drivers/net/phy/sfp-bus.c b/drivers/net/phy/sfp-bus.c
index 2f44fc51848f..f13c00b5b449 100644
--- a/drivers/net/phy/sfp-bus.c
+++ b/drivers/net/phy/sfp-bus.c
@@ -487,7 +487,7 @@ static void sfp_unregister_bus(struct sfp_bus *bus)
 			bus->socket_ops->stop(bus->sfp);
 		bus->socket_ops->detach(bus->sfp);
 		if (bus->phydev && ops && ops->disconnect_phy)
-			ops->disconnect_phy(bus->upstream);
+			ops->disconnect_phy(bus->upstream, bus->phydev);
 	}
 	bus->registered = false;
 }
@@ -722,6 +722,28 @@ void sfp_bus_del_upstream(struct sfp_bus *bus)
 }
 EXPORT_SYMBOL_GPL(sfp_bus_del_upstream);
 
+/**
+ * sfp_get_name() - Get the SFP device name
+ * @bus: a pointer to the &struct sfp_bus structure for the sfp module
+ *
+ * Gets the SFP device's name, if @bus has a registered socket. Callers must
+ * hold RTNL, and the returned name is only valid until RTNL is released.
+ *
+ * Returns:
+ *	- The name of the SFP device registered with sfp_register_socket()
+ *	- %NULL if no device was registered on @bus
+ */
+const char *sfp_get_name(struct sfp_bus *bus)
+{
+	ASSERT_RTNL();
+
+	if (bus->sfp_dev)
+		return dev_name(bus->sfp_dev);
+
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(sfp_get_name);
+
 /* Socket driver entry points */
 int sfp_add_phy(struct sfp_bus *bus, struct phy_device *phydev)
 {
@@ -743,7 +765,7 @@ void sfp_remove_phy(struct sfp_bus *bus)
 	const struct sfp_upstream_ops *ops = sfp_get_upstream_ops(bus);
 
 	if (ops && ops->disconnect_phy)
-		ops->disconnect_phy(bus->upstream);
+		ops->disconnect_phy(bus->upstream, bus->phydev);
 	bus->phydev = NULL;
 }
 EXPORT_SYMBOL_GPL(sfp_remove_phy);