Warning when compiling DTB on X-Gene platform with dtc 1.4.1-g53bf130b

Warning when compiling DTB on X-Gene platform with dtc 1.4.1-g53bf130b

[Duc Dang]

Hi Rob,

I got warning on unit_address_vs_reg similar to this
https://lkml.org/lkml/2016/3/7/43 when using v4.7-rc2 dtc to build dtb
for X-Gene Mustang:

dhdang@xgene-next=>./scripts/dtc/dtc -O dtb -R 16 -o mustang.dtb
arch/arm64/boot/dts/apm/apm-mustang.dts
  Warning (unit_address_vs_reg): Node /soc/reboot@17000014 has a unit
name, but no reg property
  Warning (unit_address_vs_reg): Node /memory has a reg or ranges
property, but no unit name
  Warning (unit_address_vs_reg): Node /gpio-keys/button@1 has a unit
name, but no reg property

There are nodes that I cannot change the node-name due to backward
compatible with old firmware reason (/soc/reboot@17000014 as an
example). Is there any other way to avoid the warning?

Regards,
Duc Dang.

Re: Warning when compiling DTB on X-Gene platform with dtc 1.4.1-g53bf130b

[Andrew Lunn]

On Tue, Jun 21, 2016 at 02:02:44AM -0700, Duc Dang wrote:
> Hi Rob,
> 
> I got warning on unit_address_vs_reg similar to this
> https://lkml.org/lkml/2016/3/7/43 when using v4.7-rc2 dtc to build dtb
> for X-Gene Mustang:
> 
> dhdang@xgene-next=>./scripts/dtc/dtc -O dtb -R 16 -o mustang.dtb
> arch/arm64/boot/dts/apm/apm-mustang.dts
>   Warning (unit_address_vs_reg): Node /soc/reboot@17000014 has a unit
> name, but no reg property
>   Warning (unit_address_vs_reg): Node /memory has a reg or ranges
> property, but no unit name
>   Warning (unit_address_vs_reg): Node /gpio-keys/button@1 has a unit
> name, but no reg property
> 
> There are nodes that I cannot change the node-name due to backward
> compatible with old firmware reason (/soc/reboot@17000014 as an
> example). Is there any other way to avoid the warning?

I think you have that backwards around. The Kernel needs to be
backwards compatible with old DT blobs. DT blobs don't generally need
to be backwards compatible to older kernels.

However, the kernel should however be happy with or without the unit
name. The unit name is pointless in this case.

	Andrew

Re: Warning when compiling DTB on X-Gene platform with dtc 1.4.1-g53bf130b

[Duc Dang]

On Tue, Jun 21, 2016 at 6:25 AM, Andrew Lunn <andrew@lunn.ch> wrote:
> On Tue, Jun 21, 2016 at 02:02:44AM -0700, Duc Dang wrote:
>> Hi Rob,
>>
>> I got warning on unit_address_vs_reg similar to this
>> https://lkml.org/lkml/2016/3/7/43 when using v4.7-rc2 dtc to build dtb
>> for X-Gene Mustang:
>>
>> dhdang@xgene-next=>./scripts/dtc/dtc -O dtb -R 16 -o mustang.dtb
>> arch/arm64/boot/dts/apm/apm-mustang.dts
>>   Warning (unit_address_vs_reg): Node /soc/reboot@17000014 has a unit
>> name, but no reg property
>>   Warning (unit_address_vs_reg): Node /memory has a reg or ranges
>> property, but no unit name
>>   Warning (unit_address_vs_reg): Node /gpio-keys/button@1 has a unit
>> name, but no reg property
>>
>> There are nodes that I cannot change the node-name due to backward
>> compatible with old firmware reason (/soc/reboot@17000014 as an
>> example). Is there any other way to avoid the warning?
>
> I think you have that backwards around. The Kernel needs to be
> backwards compatible with old DT blobs. DT blobs don't generally need
> to be backwards compatible to older kernels.
>
> However, the kernel should however be happy with or without the unit
> name. The unit name is pointless in this case.

I should be more specific: The old firmware I am talking about is the bootloader
(U-Boot). U-Boot relies on the full node names to do device tree
fix-up, so changing
the node names will break the fix-up operation in already-released U-Boot.

>
>         Andrew

Regards,
Duc Dang.