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Message-ID: <64e4b3b0-fc71-1876-9de8-e51d503d6183@linaro.org>
Date:   Mon, 16 Jan 2023 17:05:43 +0100
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Subject: Re: [PATCH] dt-bindings: qcom: geni-se: Fix '#address-cells' &
 '#size-cells' related dt-binding error
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To:     Bhupesh Sharma <bhupesh.sharma@linaro.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Cc:     linux-arm-msm@vger.kernel.org, devicetree@vger.kernel.org,
        agross@kernel.org, andersson@kernel.org,
        linux-kernel@vger.kernel.org, bhupesh.linux@gmail.com,
        robh+dt@kernel.org, krzysztof.kozlowski+dt@linaro.org
References: <20230113201038.267449-1-bhupesh.sharma@linaro.org>
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 <6f08d466-9589-ebff-c38d-bf9015a0f6ad@linaro.org>
From:   Konrad Dybcio <konrad.dybcio@linaro.org>
In-Reply-To: <6f08d466-9589-ebff-c38d-bf9015a0f6ad@linaro.org>
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On 16.01.2023 17:02, Bhupesh Sharma wrote:
> 
> On 1/16/23 9:24 PM, Konrad Dybcio wrote:
>>
>>
>> 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
> 
> 
> Have you tested this combination on SM6115 like SoCs with various IPs? I have tried a few experiments in the past and not all IPs work well with 36-bit DMA ranges (atleast not on the boards I have).
Can you list any specific examples? I've been using it for
quite some time now and I see nothing wrong..

> 
> So, I think it might lead to more breakage (unless we are sure of a well-tested fix). A simpler patch to fix the dt-bindings looks more useful IMO.
I'm not saying no, you just have to convince Krzysztof :D

Konrad

> 
> Thanks,
> Bhupesh