[PATCH] net: bcmgenet: Fix attaching to PYH failed on RPi 4B

Andrew Lunn andrew at lunn.ch
Mon Jun 21 06:09:06 PDT 2021

On Mon, Jun 21, 2021 at 06:33:11PM +0800, Jian-Hong Pan wrote:
> The Broadcom UniMAC MDIO bus comes too late. So, GENET cannot find the
> ethernet PHY on UniMAC MDIO bus. This leads GENET fail to attach the
> PHY.
> bcmgenet fd580000.ethernet: GENET 5.0 EPHY: 0x0000
> ...
> could not attach to PHY
> bcmgenet fd580000.ethernet eth0: failed to connect to PHY
> uart-pl011 fe201000.serial: no DMA platform data
> libphy: bcmgenet MII bus: probed
> ...
> unimac-mdio unimac-mdio.-19: Broadcom UniMAC MDIO bus
> This patch makes GENET try to connect the PHY up to 3 times. Also, waits
> a while between each time for mdio-bcm-unimac module's loading and
> probing.

Don't loop. Return -EPROBE_DEFER. The driver core will then probed the
driver again later, by which time, the MDIO bus driver should of


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