[PATCH] lib: utils: fdt_domain: add support for root domain region inheritance

[Yu-Chien Peter Lin]

Hi Anup,

Thanks for suggetion, I'd like to double-check before
sending v2 patch.

On Sun, May 10, 2026 at 11:34:49AM +0530, Anup Patel wrote:
> On Fri, Mar 27, 2026 at 10:04 AM Yu-Chien Peter Lin
> <peter.lin at sifive.com> wrote:
> >
> > Add the "root-regions" property in domain device-tree nodes to
> > allow domains to inherit all regions from the root domain. This
> > simplifies configuration for domains that need access to most
> > root domain regions with only minor exclusions or additions.
> 
> Overall, this is a good approach but I suggest renaming this property
> to "root-regions-inheritance" which takes the following possible values:
> 
> 1) "all" : Inherit all regions from the root domain
> 2) "su-only": Inherit regions accessible to S-mode or U-mode from the
> root domain

1. Do you mean:
   a) any root regions that have any SU permission bits set regardless of the
      M‑mode permission bits, or
   b) only regions that satisfy SBI_DOMAIN_MEMREGION_SU_ONLY_ACCESS(flags)?
2. For firmware regions marked with SBI_DOMAIN_MEMREGION_FW, should those always
   be inherited, even when "root-regions-inheritance" is "none" or "su-only"?

Thanks,
Peter Lin


> 3) "none": Inherit no regions from the root domain
> 
> From the above, if "root-regions-inheritance" is not set then it is
> assumed to be "su-only".
> 
> Regards,
> Anup