[PATCH 1/2] net: dsa: fix phydev->speed being uninitialized for the CPU port fixed PHY

Vladimir Oltean vladimir.oltean at nxp.com
Sun Dec 5 00:00:34 CET 2021

If the DSA API is going to allow drivers to do things such as:

- phy_config in dsa_ops :: port_probe
- phy_startup in dsa_ops :: port_enable

then it would actually be good if the ->port_probe() method would
actually be called in all cases before the ->port_enable() is.

Currently this is true for user ports, but not true for the CPU port,
because the CPU port does not have a udevice registered for it (this is
all part of DSA's design). So the current issue is that after
phy_startup has finished for the CPU port, its phydev->speed is an
uninitialized value, because phy_config() was never called for the
priv->cpu_port_fixed_phy, and it is precisely phy_config() who copies
the speed into the phydev in the case of the fixed PHY driver.

So we need to simulate a probing event for the CPU port by manually
calling the driver's ->port_probe() method for the CPU port.

Fixes: 8a2982574854 ("net: dsa: introduce a .port_probe() method in struct dsa_ops")
Signed-off-by: Vladimir Oltean <vladimir.oltean at nxp.com>
 net/dsa-uclass.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/net/dsa-uclass.c b/net/dsa-uclass.c
index 606b1539a776..9ff55a02fb23 100644
--- a/net/dsa-uclass.c
+++ b/net/dsa-uclass.c
@@ -466,6 +466,8 @@ static int dsa_pre_probe(struct udevice *dev)
 	struct dsa_pdata *pdata = dev_get_uclass_plat(dev);
 	struct dsa_priv *priv = dev_get_uclass_priv(dev);
+	struct dsa_ops *ops = dsa_get_ops(dev);
+	int err;
 	priv->num_ports = pdata->num_ports;
 	priv->cpu_port = pdata->cpu_port;
@@ -477,6 +479,15 @@ static int dsa_pre_probe(struct udevice *dev)
 	uclass_find_device_by_ofnode(UCLASS_ETH, pdata->master_node,
+	/* Simulate a probing event for the CPU port */
+	if (ops->port_probe) {
+		err = ops->port_probe(dev, priv->cpu_port,
+				      priv->cpu_port_fixed_phy);
+		if (err)
+			return err;
+	}
 	return 0;

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