commit d0c3601f2c4e12e7689b0f46ebc17525250ea8c3 upstream.
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>
Link: https://patch.msgid.link/20241013052916.3115142-1-o.rempel@pengutronix.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
