dtc: Empty ranges property: #cells-size warning

dtc: Empty ranges property: #cells-size warning

[Stefan Roese]

Hi,

when changing #cells-size from 1 to 2 in the root node (to support >= 4GB of 
RAM in katmai.dts) I get the following warning:

Warning (ranges_format): /plb has empty "ranges" property but its #size-cells 
(1) differs from / (2)

I could change #cells-size to 2 in the plb node as well. But this not really 
what I want, because of it's child nodes.

So my questions is: How can I solve this problem? Perhaps this warning should 
be removed from dtc?

Thanks.

Cheers,
Stefan

Re: dtc: Empty ranges property: #cells-size warning

[Segher Boessenkool]

> when changing #cells-size from 1 to 2 in the root node (to support >= 4GB
> of

You mean "#size-cells".

> RAM in katmai.dts) I get the following warning:
>
> Warning (ranges_format): /plb has empty "ranges" property but its
> #size-cells
> (1) differs from / (2)
>
> I could change #cells-size to 2 in the plb node as well. But this not
> really
> what I want, because of it's child nodes.
>
> So my questions is: How can I solve this problem? Perhaps this warning
> should
> be removed from dtc?

No, the warning is correct, and your device tree is in error.

An empty "ranges" property means that the child address space is
identical to the parent address space, which isn't the case here.

You should resolve this by using a non-empty "ranges" property,
instead.  If e.g. the address space is 1GB, and located at 0, you
would do

   < 0    0 0    0x40000000 >
(child) (parent)    (size)


Segher

Re: dtc: Empty ranges property: #cells-size warning

[David Gibson]

On Wed, Oct 21, 2009 at 06:41:22PM +0200, Segher Boessenkool wrote:
> > when changing #cells-size from 1 to 2 in the root node (to support >= 4GB
> > of
> 
> You mean "#size-cells".
> 
> > RAM in katmai.dts) I get the following warning:
> >
> > Warning (ranges_format): /plb has empty "ranges" property but its
> > #size-cells
> > (1) differs from / (2)
> >
> > I could change #cells-size to 2 in the plb node as well. But this not
> > really
> > what I want, because of it's child nodes.
> >
> > So my questions is: How can I solve this problem? Perhaps this warning
> > should
> > be removed from dtc?
> 
> No, the warning is correct, and your device tree is in error.
> 
> An empty "ranges" property means that the child address space is
> identical to the parent address space, which isn't the case here.
> 
> You should resolve this by using a non-empty "ranges" property,
> instead.  If e.g. the address space is 1GB, and located at 0, you
> would do
> 
>    < 0    0 0    0x40000000 >
> (child) (parent)    (size)

Exactly.  An empty ranges property makes no sense if the parent and
child address spaces aren't identical.  You need an explicit ranges
property to show how the child address space is embedded in the
parent's.

-- 
David Gibson			| 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

Re: dtc: Empty ranges property: #cells-size warning

[Stefan Roese]

On Thursday 22 October 2009 00:04:13 David Gibson wrote:
> > No, the warning is correct, and your device tree is in error.
> >
> > An empty "ranges" property means that the child address space is
> > identical to the parent address space, which isn't the case here.
> >
> > You should resolve this by using a non-empty "ranges" property,
> > instead.  If e.g. the address space is 1GB, and located at 0, you
> > would do
> >
> >    < 0    0 0    0x40000000 >
> > (child) (parent)    (size)
> 
> Exactly.  An empty ranges property makes no sense if the parent and
> child address spaces aren't identical.  You need an explicit ranges
> property to show how the child address space is embedded in the
> parent's.

OK, thanks for making this clear.

Cheers,
Stefan