[linux-sunxi] Re: [PATCH 3/6] ARM: dts: sunxi: Add Allwinner A80 dtsi

Chen-Yu Tsai wens at csie.org
Wed Sep 24 04:53:33 PDT 2014

On Wed, Sep 24, 2014 at 3:18 PM, Gregory CLEMENT
<gregory.clement at free-electrons.com> wrote:
> Hi Chen-Yu,
>>>> +
>>>> +     memory {
>>>> +             reg = <0x20000000 0x40000000>;
>>> Usually, what we put there was the maximum amount of RAM that can be
>>> handled by the SoC. I think that it can go above 1GB
>> With LPAE, it can handle 8GB. But the DT won't take 64bit values.
>> I'm not sure how to get it in. I'll look around for examples.
> You can have a look on what we did for Armada XP:
> arch/arm/boot/dts/armada-370-xp.dtsi
> arch/arm/boot/dts/armada-xp.dtsi
> arch/arm/boot/dts/armada-xp-gp.dts
> I created a skeleton64.dtsi for this case

Thanks for the tip. Before I send v2, I do have a question. I'm using

    ranges = <0 0 0 0x20000000>;

in the clocks and soc node to avoid having to use 64bit values for all
addresses and sizes. Would this be undesirable, even bad practice maybe?

http://linux-sunxi.org/A80/Memory_map is a document I pieced together
from Allwinner's SDK header files. AFAIK only the memory goes above
the 4GB limit. All peripherals are under 512 MB, 256MB even.


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