Re: [PATCH u-boot v2] ARM: dts: aspeed: Add dts for ASUS Kommando IPMI card

Hi Andrew,

On Mon, May 18, 2026 at 7:59 AM Andrew Jeffery
<[email protected]> wrote:
>
> Hi Anirudh,
>
> Sorry for the delay :(
>
> On Sat, 2026-03-28 at 14:14 -0500, Anirudh Srinivasan wrote:
> > Add dts for Asus Kommando IPMI card, an ast2600 based pcie bmc card.
> >
> > This version of the DTS doesn't support networking due to u-boot inserting
> > mac delays (when it isn't really needed) and needing to misconfigure the
> > phy-mode in linux due to it. See discussion here [1] for more details.
> >
> > Networking can be enabled in this manner currently.
> >
> > aliases {
> >         eth0 = &mac2;
> > };
> >
> > &mac2 {
> >       status = "okay";
> >       phy-mode = "rgmii-id";
> >       phy-handle = <&ethphy2>;
> >       pinctrl-names = "default";
> >       pinctrl-0 = <&pinctrl_rgmii3_default>;
> > };
> >
> > &mdio {
> >        status = "okay";
> >        pinctrl-names = "default";
> >        pinctrl-0 = <&pinctrl_mdio3_default>;
> >        #address-cells = <1>;
> >        #size-cells = <0>;
> >
> >        ethphy2: ethernet-phy@2 {
> >                reg = <0>;
> >        };
> > };
> >
> > &scu {
> >        mac2-clk-delay = <0 0
> >                          0 0
> >                          0 0>;
> > };
>
> So something I didn't appreciate in our previous discussion was that
> this was a property on the SCU node (I should have looked then).
> Checking the implementation, it seems to me like this is the same as
> not specifying the property. That corroborates Ender's efforts here:
>
> https://lore.kernel.org/all/[email protected]/
>
> I think we just drop the property and add in the mac nodes, and remove
> this note from the commit message?
>
> Possibly some confusion comes from the EVB DTS specifying the property,
> and everyone just copied it, then wondered why it was all broken.

I think that the u-boot implementation [1] uses a default value for
the clk delay if it doesn't find a clk-delay node in the DT. My
testing also seemed to suggest this, i.e if I dropped the clk-delay
node node, networking wasn't working. We need a zero clk delay, and
the default isn't zero.

Am I correct? I can try testing again when I get some time later on in the week.

I looked through Ender's efforts and it seems surprising that it works
for their board. Maybe the board design is different in some manner
there?

>
> Andrew


[1] https://github.com/openbmc/u-boot/blob/17ae8f018476af91f9c80da8e9ec9ef218e0b6de/drivers/clk/aspeed/clk_ast2600.c#L980
-- 
Regards
Anirudh Srinivasan