Hi Geert-san,
Thank you for your review!
> From: Geert Uytterhoeven, Sent: Thursday, January 27, 2022 8:06 PM
>
> Hi Shimoda-san,
>
> CC Laurent, Magnus.
>
> On Tue, Jan 25, 2022 at 6:33 PM Yoshihiro Shimoda
> <yoshihiro.shimoda.uh@xxxxxxxxxxx> wrote:
> > Document the compatible values for the IPMMU-VMSA blocks in
> > the Renesas R-Car S4-8 (R8A779F0) SoC and R-Car Gen4.
> >
> > Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@xxxxxxxxxxx>
>
> Thanks for your patch!
>
> > --- a/Documentation/devicetree/bindings/iommu/renesas,ipmmu-vmsa.yaml
> > +++ b/Documentation/devicetree/bindings/iommu/renesas,ipmmu-vmsa.yaml
> > @@ -44,6 +44,10 @@ properties:
> > - renesas,ipmmu-r8a77990 # R-Car E3
> > - renesas,ipmmu-r8a77995 # R-Car D3
> > - renesas,ipmmu-r8a779a0 # R-Car V3U
> > + - items:
> > + - enum:
> > + - renesas,ipmmu-r8a779f0 # R-Car S4-8
> > + - const: renesas,rcar-gen4-ipmmu-vmsa # R-Car Gen4
> >
>
> I'm wondering if we need the family-specific fallback.
> For R-Car Gen3, we don't have it, and match on (all) the SoC-specific
> compatible values instead.
> Do you remember why we decided to do it that way?
>
> At least R-Car V3M/V3H/D3 have slight differences in the register bits,
> but I don't think that was the reason.
I don't remember why... Maybe, we had never discussed this topic?
I searched this topic a little on the ML archive, but I could not find it...
Since upcoming R-Car Gen4 SoC's IPMMU is the same specification with r8a779f0,
I believe renesas,rcar-gen4-ipmmu-vmsa is helpful to support it.
Best regards,
Yoshihiro Shimoda
>
> Gr{oetje,eeting}s,
>
> Geert
>
> --
> Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
>
> In personal conversations with technical people, I call myself a hacker. But
> when I'm talking to journalists I just say "programmer" or something like that.
> -- Linus Torvalds
