[PATCH 1/2] arm64: dts: juno/vexpress: fix node name unit-address presence warnings

Rob Herring robh+dt at kernel.org
Fri Mar 18 07:52:51 PDT 2016


On Fri, Mar 18, 2016 at 9:15 AM, Jon Medhurst (Tixy) <tixy at linaro.org> wrote:
> On Fri, 2016-03-18 at 08:09 -0500, Rob Herring wrote:
>> On Fri, Mar 18, 2016 at 5:32 AM, Jon Medhurst (Tixy) <tixy at linaro.org> wrote:
>> > On Thu, 2016-03-17 at 16:44 -0500, Rob Herring wrote:
>> >> On Mon, Mar 7, 2016 at 6:12 AM, Sudeep Holla <sudeep.holla at arm.com> wrote:
> [...]
>> >> > Let me know.
>> >> >
>> >> > Regards,
>> >> > Sudeep
>> >> >
>> >> > diff --git a/arch/arm64/boot/dts/arm/foundation-v8.dtsi b/arch/arm64/boot/dts/arm/foundation-v8.dtsi
>> >> > index 9314f3943269..ba03c934a861 100644
>> >> > --- a/arch/arm64/boot/dts/arm/foundation-v8.dtsi
>> >> > +++ b/arch/arm64/boot/dts/arm/foundation-v8.dtsi
>> >> > @@ -89,7 +89,7 @@
>> >> >                              <0 63 4>;
>> >> >         };
>> >> >
>> >> > -       smb {
>> >> > +       smb at 0,08000000 {
>> >>
>> >> Drop the comma and leading zeros. Comma is for distinct fields like
>> >> bus,dev,func on PCI.
>> >
>> > So what is the correct way of representing 2 cell addresses? Not just
>> > those that are logically 64-bit addresses, (which I guess could be just
>> > a single number), but things like vexpress motherboard where we have
>> > Chip-select and Offset values?
>>
>> 64-bit address is just a single number.
>> 2 cells with distinct fields should generally be ...@<cell1>,<cell2>
>>
>> If you have your own bus type, you can devise whatever you like as
>> long as it is reviewed.
>>
>> > I looked at ePAPR but it just says 'The unit-address must
>> > match the first address specified in the reg property of the node.' and
>> > lists valid characters for unit address, which includes ,._+-
>>
>> Yes, we need to clarify this some.
>
> Yes, because there is already quite a bit of use of @X,Y for two cell
> 64-bit addresses (Tegra mostly, I assume they're 64-bit addresses).

That is because briefly we were telling folks to do that until Ben H
clarified when commas are appropriate.

> And for 32-bit addresses lots of use of leading zeros to pad address to
> consistence number of digits, both in unit names and in reg properties.
>
> $ grep '@0[^ ^,]' -R arch/arm/boot/dts | wc -l
> 1300

I'm working on dtc checks for both. I also learned yesterday some TI
DTs use the full address rather than the local untranslated address.

Rob



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