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Date:   Mon, 9 Jan 2023 23:36:18 +0200
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Subject: Re: [PATCH v4 1/2] dt-bindings: arm: qcom: Document the sc7280 CRD
 Pro boards
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To:     Doug Anderson <dianders@chromium.org>, andersson@kernel.org
Cc:     Rajendra Nayak <quic_rjendra@quicinc.com>,
        Matthias Kaehlcke <mka@chromium.org>, agross@kernel.org,
        robh+dt@kernel.org, krzysztof.kozlowski+dt@linaro.org,
        konrad.dybcio@linaro.org, linux-arm-msm@vger.kernel.org,
        devicetree@vger.kernel.org, linux-kernel@vger.kernel.org
References: <20221216112918.1243-1-quic_rjendra@quicinc.com>
 <Y5x+WEwTtpoV0gaR@google.com>
 <fd23e295-fea0-1b0a-752c-3cce26b57346@quicinc.com>
 <Y6HHCrl0q5BhrHOY@google.com>
 <e269300d-539e-9eb8-8b3c-d309f3abca1b@quicinc.com>
 <bbc3c257-0a49-4c80-4586-c179c8997b50@linaro.org>
 <CAD=FV=X3DyMrEWESV2cWvqg_TQYnj+VGFBQodAp+gfbhBz6X3Q@mail.gmail.com>
From:   Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
In-Reply-To: <CAD=FV=X3DyMrEWESV2cWvqg_TQYnj+VGFBQodAp+gfbhBz6X3Q@mail.gmail.com>
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On 09/01/2023 23:00, Doug Anderson wrote:
> Hi,
> 
> On Tue, Dec 20, 2022 at 9:12 AM Dmitry Baryshkov
> <dmitry.baryshkov@linaro.org> wrote:
>>
>> On 20/12/2022 18:20, Rajendra Nayak wrote:
>>>
>>>
>>> On 12/20/2022 8:00 PM, Matthias Kaehlcke wrote:
>>>> On Tue, Dec 20, 2022 at 10:30:32AM +0530, Rajendra Nayak wrote:
>>>>>
>>>>> On 12/16/2022 7:49 PM, Matthias Kaehlcke wrote:
>>>>>> On Fri, Dec 16, 2022 at 04:59:17PM +0530, Rajendra Nayak wrote:
>>>>>>> Add compatibles for the Pro SKU of the sc7280 CRD boards
>>>>>>> which come with a Pro variant of the qcard.
>>>>>>> The Pro qcard variant has smps9 from pm8350c ganged up with
>>>>>>> smps7 and smps8.
>>>>>>>
>>>>>>> Signed-off-by: Rajendra Nayak <quic_rjendra@quicinc.com>
>>>>>>> Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
>>>>>>> Reviewed-by: Matthias Kaehlcke <mka@chromium.org>
>>>>>>> ---
>>>>>>> v4 changes:
>>>>>>> Added the zoglin-sku1536 compatible along with hoglin-sku1536.
>>>>>>> Zoglin is same as the Hoglin variant, with the SPI Flash reduced
>>>>>>> from 64MB to 8MB
>>>>>>>
>>>>>>>     Documentation/devicetree/bindings/arm/qcom.yaml | 6 ++++++
>>>>>>>     1 file changed, 6 insertions(+)
>>>>>>>
>>>>>>> diff --git a/Documentation/devicetree/bindings/arm/qcom.yaml
>>>>>>> b/Documentation/devicetree/bindings/arm/qcom.yaml
>>>>>>> index 1b5ac6b02bc5..07771d4c91bd 100644
>>>>>>> --- a/Documentation/devicetree/bindings/arm/qcom.yaml
>>>>>>> +++ b/Documentation/devicetree/bindings/arm/qcom.yaml
>>>>>>> @@ -558,6 +558,12 @@ properties:
>>>>>>>               - const: google,hoglin
>>>>>>>               - const: qcom,sc7280
>>>>>>> +      - description: Qualcomm Technologies, Inc. sc7280 CRD Pro
>>>>>>> platform (newest rev)
>>>>>>> +        items:
>>>>>>> +          - const: google,zoglin-sku1536
>>>>>>> +          - const: google,hoglin-sku1536
>>>>>>
>>>>>> Is there actually such a thing as a 'hoglin-sku1536', i.e. the Pro
>>>>>> qcard
>>>>>> with 64MB of SPI flash, or do they all have 8MB of flash?
>>>>>
>>>>> The SPI flash is on the CRD mother-board and not on the qcards, so if
>>>>> you replace
>>>>> the qcards on the CRDs with 64MB flash you would need the
>>>>> hoglin-sku1536 to
>>>>> boot on those.
>>>>
>>>> With such a configuration how does the bootloader know it should pass
>>>> the kernel
>>>> the device tree for 'hoglin-sku1536' (pro) and not the non-pro
>>>> variant? IIUC the
>>>> device tree is selected based on pin strappings on the mother-board,
>>>> not the
>>>> qcard.
>>>
>>> The device tree is selected based on the pin strappings _and_ additional
>>> logic
>>> to dynamically identify modem/non-modem(wifi) as well as pro/non-pro
>>> SKUs which
>>> was added in the bootloaders.
>>
>> Just to clarify things, when you mention pro SKU, is it a separate SoC
>> revision (like sc7280-pro vs bare sc7280), or is it a CRD revision (CRD
>> Pro vs bare CRD)?
> 
> I guess Rajendra never responded, but since I know the answer: it's a
> different SoC revision. ...but the SoC in this case is on a daughter
> card, so you could remove the daughter card containing the SoC and put
> a new daughtercard on. That would have the effect of making an old CRD
> revision have the new Pro SKU SoC.

So, this is a new SoC. Is it 100% compatible with the sc7280? In other 
words: does it require any additional customizations (in OPP tables, in 
frequences, speed bins, etc)?

> 
> Bjorn: I'd also note that I think this series (this patch and the next
> one) are ready to land.
> 
> -Doug

-- 
With best wishes
Dmitry