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    SubjectRe: [PATCH v4 1/2] dt-bindings: arm: qcom: Document the sc7280 CRD Pro boards
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    On 1/10/2023 3:12 AM, Doug Anderson wrote:
    > Hi,
    >
    > On Mon, Jan 9, 2023 at 1:36 PM Dmitry Baryshkov
    > <dmitry.baryshkov@linaro.org> wrote:
    >>
    >> 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

    Thanks Doug for the clarifications, I seem to have missed responding to this
    once I was back from vacation,

    >>> 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)?

    Yes, the OPP differences are taken care of with no changes needed in kernel.
    We describe a superset of *all* OPPs supported by a SoC family in DT and the
    cpufreq driver then queries the firmware for supported OPPs on a given
    SoC variant and ends up disabling the rest.

    >
    > If I understand correctly, the OPP customizations have been accounted
    > for since the beginning. I believe that the GPU operating table
    > already has some fairly high operating points. Maybe commit
    > 3bfef00d7671 ("arm64: dts: qcom: sc7280: Support gpu speedbin") was
    > for pro? Similarly, the CPU operating table also has some fairly high
    > operating points (probably for PRO?) and I think the higher points are
    > dynamically disabled for CPUs that don't support them. That's how it
    > was on sc7180, in any case.
    >
    > ...I will say it's not 100% compatible, though. Patch #2 in this
    > series deletes "vreg_s9c_0p676" on pro SKUs. As far as I know, that's
    > the only needed change, though.
    >
    > -Doug

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