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

[Alastair D'Silva]

On Tue, 2026-09-15 at 23:12 -0600, James Hilliard wrote:
> On Tue, Sep 15, 2026 at 10:56 PM Chen-Yu Tsai <wens@xxxxxxxxxx>
> wrote:
> > 
<snip>
> > There is already a series from James covering the same thing.
> > Please check
> > the mailing list and possibly our wiki (linux-sunxi.org) to avoid
> > duplicate
> > work and subjecting the maintainers to the same discussions again.
> 
> See:
> https://git.kernel.org/netdev/net-next/c/783f6f1fdcd5
> https://git.kernel.org/netdev/net-next/c/6cc2fbceb49b
> https://lore.kernel.org/all/20260915-submit-h616-emac1-v1-v2-2-
> 322b32e40eb9@xxxxxxxxx/
> > > 

Thanks, I'll withdraw this series.


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.

Cheers,

-- 
Alastair D'Silva