On Tue, Aug 24, 2021 at 12:00 PM Pavel Machek pavel@denx.de wrote:
Hi1
When registering mdiobus children, if we get an -EPROBE_DEFER, we shouldn't ignore it and continue registering the rest of the mdiobus children. This would permanently prevent the deferring child mdiobus from working instead of reattempting it in the future. So, if a child mdiobus needs to be reattempted in the future, defer the entire mdio-mux initialization.
This fixes the issue where PHYs sitting under the mdio-mux aren't initialized correctly if the PHY's interrupt controller is not yet ready when the mdio-mux is being probed. Additional context in the link below.
I don't believe this is quite right. AFAICT it leaks memory in the EPROBE_DEFER case. Could someone double-check? Suggested fix is below.
devm_ APIs would take care of releasing the resource (memory) automatically because the probe didn't succeed. So I'm not sure there's a leak. Does that make sense?
-Saravana
+++ b/drivers/net/mdio/mdio-mux.c @@ -175,11 +175,15 @@ int mdio_mux_init(struct device *dev, cb->mii_bus->write = mdio_mux_write; r = of_mdiobus_register(cb->mii_bus, child_bus_node); if (r) {
mdiobus_free(cb->mii_bus);if (r == -EPROBE_DEFER) {ret_val = r;goto err_loop;}devm_kfree(dev, cb); dev_err(dev, "Error: Failed to register MDIO bus for child %pOF\n", child_bus_node);
mdiobus_free(cb->mii_bus);devm_kfree(dev, cb); } else { cb->next = pb->children; pb->children = cb;Signed-off-by: Pavel Machek (CIP) pavel@denx.de
diff --git a/drivers/net/mdio/mdio-mux.c b/drivers/net/mdio/mdio-mux.c index ccb3ee704eb1..6d0e505343c5 100644 --- a/drivers/net/mdio/mdio-mux.c +++ b/drivers/net/mdio/mdio-mux.c @@ -163,6 +163,7 @@ int mdio_mux_init(struct device *dev, cb->mii_bus = mdiobus_alloc(); if (!cb->mii_bus) { ret_val = -ENOMEM;
devm_kfree(dev, cb); goto err_loop; } cb->mii_bus->priv = cb;@@ -176,11 +177,11 @@ int mdio_mux_init(struct device *dev, r = of_mdiobus_register(cb->mii_bus, child_bus_node); if (r) { mdiobus_free(cb->mii_bus);
devm_kfree(dev, cb); if (r == -EPROBE_DEFER) { ret_val = r; goto err_loop; }
devm_kfree(dev, cb); dev_err(dev, "Error: Failed to register MDIO bus for child %pOF\n", child_bus_node);-- DENX Software Engineering GmbH, Managing Director: Wolfgang Denk HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany