Re: Devicetree spec: Specifying /cpus/cpu@* unit address format?

David Gibson <[email protected]> Sun, 5 Apr 2026 14:43:41 +1000

Newsgroups	dev.linux.lists.sophgo,org.infradead.lists.linux-riscv,org.kernel.vger.devicetree-spec,org.kernel.vger.linux-devicetree
Message-ID	<adHofcKAr7C5YCSA@zatzit>

On Fri, Apr 03, 2026 at 06:06:17PM +0800, Vivian Wang wrote:
> (Also posted at: https://github.com/devicetree-org/devicetree-specification/issues/86 )
> 
> Hi all,
> 
> Presently, there seems to be some confusion in the community about the
> format of unit addresses for "/cpus/cpu@*" nodes for a CPU with ID > 9, e.g.
> 
>     cpu@??? {
>         reg = <10>;
>         /* reg = <0xa>; */ /* This should be equivalent */
>     }
> 
> 
> Should this be a decimal "cpu@10", or hexadecimal "cpu@a"? I can't find
> any explicit specification.

It should be hex.  That's a general convention for unit addresses.
Before flattened trees, OF essentially never used decimal
representations of things.

-- 
David Gibson (he or they)	| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you, not the other way
				| around.
http://www.ozlabs.org/~dgibson

signature.asc (application/pgp-signature, 833 B)