Re: [PATCH v2 4/4] arm: dts: visconti: Add DT support for Toshiba Visconti5 ethernet controller

[Arnd Bergmann]

On Fri, Feb 12, 2021 at 4:03 AM Nobuhiro Iwamatsu
<nobuhiro1.iwamatsu@xxxxxxxxxxxxx> wrote:
> @@ -384,6 +398,16 @@ spi6: spi@28146000 {
>                         #size-cells = <0>;
>                         status = "disabled";
>                 };
> +
> +               piether: ethernet@28000000 {
> +                       compatible = "toshiba,visconti-dwmac";

Shouldn't there be a more specific compatible string here, as well as the
particular version of the dwmac you use?

In the binding example, you list the device as "dma-coherent",
but in this instance, it is not marked that way. Can you find out
whether the device is in fact connected properly to a cache-coherent
bus?

Note that failing to mark it as cache-coherent will make the device
rather slow and possibly not work correctly if it is in fact coherent,
but the default is non-coherent since a lot of SoCs are lacking
that hardware support.

       Arnd