Re: [PATCH] dt-bindings: qcom: geni-se: Fix '#address-cells' & '#size-cells' related dt-binding error

[Konrad Dybcio <konrad.dybcio@linaro.org>]

On 16.01.2023 16:43, Bhupesh Sharma wrote:
> On Mon, 16 Jan 2023 at 13:23, Krzysztof Kozlowski
> <krzysztof.kozlowski@linaro.org> wrote:
>>
>> On 15/01/2023 22:33, Bhupesh Sharma wrote:
>>> On Sun, 15 Jan 2023 at 20:57, Krzysztof Kozlowski
>>> <krzysztof.kozlowski@linaro.org> wrote:
>>>>
>>>> On 13/01/2023 21:10, Bhupesh Sharma wrote:
>>>>> Fix the following '#address-cells' & '#size-cells' related
>>>>> dt-binding error:
>>>>>
>>>>>    $ make dtbs_check
>>>>>
>>>>>    From schema: Documentation/devicetree/bindings/soc/qcom/qcom,geni-se.yaml
>>>>>         arch/arm64/boot/dts/qcom/sm4250-oneplus-billie2.dtb: geniqup@4ac0000:
>>>>>               #address-cells:0:0: 2 was expected
>>>>>       From schema: Documentation/devicetree/bindings/soc/qcom/qcom,geni-se.yaml
>>>>
>>>> Don't we want rather to unify the soc address range?
>>>
>>> Well, the assumption in the original dt-bindings was that every reg
>>> variable is 4 * u32 wide (as most new qcom SoCs set #address- and
>>> #size-cells to <2>). However, that is not the case for all of the
>>> SoCs.
>>
>> Hm, which device of that SoC cannot be used with address/size cells 2?
> 
> As noted in the git log already the geniqup on sm6115 / sm4250 cannot
> be used with address/size cells 2 (See:
> https://github.com/torvalds/linux/blob/master/arch/arm64/boot/dts/qcom/sm6115.dtsi#L795)
SM6115 (and pretty much every other arm64 msm platform newer than 8916)
should be using addr/size-cells = 2 along with (dma-)ranges of 36 bit, as
that's what their smmus use and otherwise some addresses may get cut off
in translation, or so the story went with 845 N years ago.. We can either
pursue this patch or I can submit the 2-cell-ification if you don't plan on
adding more nodes shortly

Konrad
> 
>>> So, ideally we shouldn't set the  "#address-cells" and  "#size-cells":
>>> as const: 2 in the bindings.
>>>
>>> See as an example:
>>> https://www.kernel.org/doc/Documentation/devicetree/bindings/usb/usb-device.yaml
>>
>>
>> How USB device - so entirely different device, not MMIO! - is related here?
>>
>> Best regards,
>> Krzysztof
>>