Re: [PATCH net-next 0/4] net: Add Allwinner H616/H618 EMAC1 and AC300 EPHY support

[Maxime Chevallier]

Hi,
On 9/16/26 08:49, Alastair D'Silva wrote:

> There is one subtle timing issue worth highlighting from our Armbian
> testing on the Mellow Fly-C5 (H618):
> 
> In James's dwmac patch, setting soc_has_internal_phy = false causes
> sun8i_dwmac_probe() to fall through to sun8i_dwmac_reset(priv). The
> Synopsys EMAC DMA soft reset (EMAC_BASIC_CTL1 bit 0) requires a running
> RMII clock from the PHY to clear.
> 
> While this reset succeeds when the PHY driver is built-in and probes
> synchronously, if CONFIG_XPOWERS_ACX00_PHY is built as a module (=m)
> or if the PHY probe defers (-EPROBE_DEFER on regulator/clock/nvmem),
> the PHY is unpowered and not clocking when sun8i_dwmac_probe() runs.
> 
> This causes sun8i_dwmac_reset() to time out after 100ms ("EMAC reset
> timeout"), failing MAC driver probe. In our testing, deferring the MAC
> reset until sun8i_dwmac_init() (which runs upon ndo_open after phylink
> has attached and the PHY is active) avoided this probe failure.

I'm OK with going with James' version, however this seems like a valid
point that needs to be figured out.

James, can you add Alastair in CC of your next iterations, and Alastair
it would be great if you could give James's patches a test when he
submits them :)

There's more stuff in the dwmac part for Alastair's version, some
-EPROBEFER handling for clocks, the reset thing as well as the MUX
part, for which use-cases is all of that required ?

If that's something that needs to land with proper EMAC1 support, maybe
this could be split out from Alastair's work (in individual patches
please), and integrated in James's series ?

Maxime