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 Reviewed-by: Andrew Lunn andrew@lunn.ch --- changes v2: - s/some PHYs may be attached/some devices may be attached/ --- drivers/net/ethernet/cadence/macb_main.c | 14 +++++++++++--- 1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/drivers/net/ethernet/cadence/macb_main.c b/drivers/net/ethernet/cadence/macb_main.c index f06babec04a0b..56901280ba047 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 devices 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));