[PATCH 11/14] arm64: dts: Add initial device tree support for EXYNOS7

[Rob Herring]

On Thu, Aug 28, 2014 at 12:19 PM, Olof Johansson <olof at lixom.net> wrote:
> On Thu, Aug 28, 2014 at 10:03 AM, Mark Rutland <mark.rutland at arm.com> wrote:
>> On Thu, Aug 28, 2014 at 05:28:22PM +0100, Olof Johansson wrote:
>>> On Thu, Aug 28, 2014 at 2:48 AM, Mark Rutland <mark.rutland at arm.com> wrote:
>>> > Hi,
>>> >
>>> >> > +   cpus {
>>> >> > +           #address-cells = <2>;
>>> >> > +           #size-cells = <0>;
>>> >>
>>> >> Why size-cells=2? Can you not fit a cpuid in 32 bits?
>>> >
>>> > As of commit 72aea393a2e7 (arm64: smp: honour #address-size when parsing
>>> > CPU reg property) Linux can handle single-cell cpu node reg entries
>>> > where /cpus/#address-cells = <1>.
>>> >
>>> > I can't make any guarantees about other code (e.g. bootloaders) which
>>> > might try to do things with cpu nodes, YMMV.
>>>
>>> Ok. If address-cells is kept at 2 the unit address needs to be changed
>>> to "0,0". So one or the other has to be changed.
>>
>> I'm happy either way.
>>
>> I'm not sure the rest of the tree had "0," prefixes on all of the
>> unit-addresses for 64-bit addresses that were under 4GB, and I'm not
>> sure that existing dts consistently do that either.
>>
>> Do we want to enforce that for all 64-bit unit-addresses?
>
> Yeah, I believe that's the only valid format for a 2-address-cell unit address.

But we don't do leading 0's anywhere else like single cell unit
addresses. Buses expressed with ranges and offsets are one example.
Also, I2C addresses have a 32-bit size in DT yet are only 8-bit and we
don't do leading zero's there.

Rob