Re: [PATCH 1/3] arm64: dts: berlin4ct: add missing unit name to /soc node

From: Stephen Warren
Date: Tue Sep 06 2016 - 12:05:11 EST


On 09/06/2016 04:57 AM, Mark Rutland wrote:
On Tue, Sep 06, 2016 at 06:20:48PM +0800, Jisheng Zhang wrote:
Hi Mark,

On Tue, 6 Sep 2016 11:22:08 +0100 Mark Rutland wrote:

On Tue, Sep 06, 2016 at 04:55:55PM +0800, Jisheng Zhang wrote:
This patch fixes the following DTC warning with W=1:

"Node /soc has a reg or ranges property, but no unit name"

Signed-off-by: Jisheng Zhang <jszhang@xxxxxxxxxxx>

The node is only compatible with simple-bus, and so shouldn't have a
reg.

IIUC, the warning is caused by "ranges = <0 0 0xf7000000 0x1000000>;"

Hmm.. I've rather confused by that warning. Per ePAPR and the
devicetree.org spec, the unit-addresss is meant to match the reg
property, and no mention is made of the ranges property. So I do not
think that it is necessary to require this.

That warning seems to have gone into DTC in commit c9d9121683b35281
("Warn on node name unit-address presence/absence mismatch").

Rob, Stephen, was there some discussion that prompted ranges requiring
a matching unit-address?

It looks like there was some in response to V2 of the patch which introduced this warning in dtc:

https://lkml.org/lkml/2013/9/19/301

I assume that's why Rob added that part to the patch when he reposted it.