| Message ID | 20241010105101.3128090-1-o.rempel@pengutronix.de (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [net,v1,1] net: macb: Avoid 20s boot delay by skipping MDIO bus registration for fixed-link PHY | expand |
> diff --git a/drivers/net/ethernet/cadence/macb_main.c b/drivers/net/ethernet/cadence/macb_main.c > index f06babec04a0b..e4ee55bc53ba7 100644 > --- a/drivers/net/ethernet/cadence/macb_main.c > +++ b/drivers/net/ethernet/cadence/macb_main.c > @@ -930,9 +930,6 @@ static int macb_mdiobus_register(struct macb *bp) > return ret; > } > > - if (of_phy_is_fixed_link(np)) > - return mdiobus_register(bp->mii_bus); > - > /* Only create the PHY from the device tree if at least one PHY is > * described. Otherwise scan the entire MDIO bus. We do this to support > * old device tree that did not follow the best practices and did not > @@ -953,8 +950,19 @@ static int macb_mdiobus_register(struct macb *bp) > > static int macb_mii_init(struct macb *bp) > { > + struct device_node *child, *np = bp->pdev->dev.of_node; > int err = -ENXIO; > > + /* With fixed-link, we don't need to register the MDIO bus, > + * except if we have a child named "mdio" in the device tree. > + * In that case, some PHYs may be attached to the MACB's MDIO bus. nitpick. It could be a switch on the MDIO bus, so "some devices may be" > + */ > + child = of_get_child_by_name(np, "mdio"); > + if (child) > + of_node_put(child); The code now gets this node twice. You could add an optimisation patch which passed child to macb_mdiobus_register(). Reviewed-by: Andrew Lunn <andrew@lunn.ch> Andrew
diff --git a/drivers/net/ethernet/cadence/macb_main.c b/drivers/net/ethernet/cadence/macb_main.c index f06babec04a0b..e4ee55bc53ba7 100644 --- a/drivers/net/ethernet/cadence/macb_main.c +++ b/drivers/net/ethernet/cadence/macb_main.c @@ -930,9 +930,6 @@ static int macb_mdiobus_register(struct macb *bp) return ret; } - if (of_phy_is_fixed_link(np)) - return mdiobus_register(bp->mii_bus); - /* Only create the PHY from the device tree if at least one PHY is * described. Otherwise scan the entire MDIO bus. We do this to support * old device tree that did not follow the best practices and did not @@ -953,8 +950,19 @@ static int macb_mdiobus_register(struct macb *bp) static int macb_mii_init(struct macb *bp) { + struct device_node *child, *np = bp->pdev->dev.of_node; int err = -ENXIO; + /* With fixed-link, we don't need to register the MDIO bus, + * except if we have a child named "mdio" in the device tree. + * In that case, some PHYs may be attached to the MACB's MDIO bus. + */ + child = of_get_child_by_name(np, "mdio"); + if (child) + of_node_put(child); + else if (of_phy_is_fixed_link(np)) + return macb_mii_probe(bp->dev); + /* Enable management port */ macb_writel(bp, NCR, MACB_BIT(MPE));
A boot delay was introduced by commit 79540d133ed6 ("net: macb: Fix handling of fixed-link node"). This delay was caused by the call to `mdiobus_register()` in cases where a fixed-link PHY was present. The MDIO bus registration triggered unnecessary PHY address scans, leading to a 20-second delay due to attempts to detect Clause 45 (C45) compatible PHYs, despite no MDIO bus being attached. The commit 79540d133ed6 ("net: macb: Fix handling of fixed-link node") was originally introduced to fix a regression caused by commit 7897b071ac3b4 ("net: macb: convert to phylink"), which caused the driver to misinterpret fixed-link nodes as PHY nodes. This resulted in warnings like: mdio_bus f0028000.ethernet-ffffffff: fixed-link has invalid PHY address mdio_bus f0028000.ethernet-ffffffff: scan phy fixed-link at address 0 ... mdio_bus f0028000.ethernet-ffffffff: scan phy fixed-link at address 31 This patch reworks the logic to avoid registering and allocation of the MDIO bus when: - The device tree contains a fixed-link node. - There is no "mdio" child node in the device tree. If a child node named "mdio" exists, the MDIO bus will be registered to support PHYs attached to the MACB's MDIO bus. Otherwise, with only a fixed-link, the MDIO bus is skipped. Tested on a sama5d35 based system with a ksz8863 switch attached to macb0. Fixes: 79540d133ed6 ("net: macb: Fix handling of fixed-link node") Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de> Cc: stable@vger.kernel.org --- drivers/net/ethernet/cadence/macb_main.c | 14 +++++++++++--- 1 file changed, 11 insertions(+), 3 deletions(-) -- 2.39.5