Message-ID: <bced492e-08f3-90d9-4ca0-41ab0e4cca9d@linaro.org>
Date:   Wed, 1 Feb 2023 08:12:53 +0100
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Subject: Re: [PATCH 2/2] clk: qcom: restrict drivers per ARM/ARM64
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To:     Stephen Boyd <sboyd@kernel.org>, Andy Gross <agross@kernel.org>,
        Bjorn Andersson <andersson@kernel.org>,
        Konrad Dybcio <konrad.dybcio@linaro.org>,
        Michael Turquette <mturquette@baylibre.com>,
        linux-arm-msm@vger.kernel.org, linux-clk@vger.kernel.org,
        linux-kernel@vger.kernel.org
References: <20230123094925.54824-1-krzysztof.kozlowski@linaro.org>
 <20230123094925.54824-2-krzysztof.kozlowski@linaro.org>
 <7ddf5c74de84c5dc291996423cb1eb46.sboyd@kernel.org>
 <febd59ed-ff7b-ffc4-5568-d856703c9123@linaro.org>
 <9367139a425dc7e4811c757b62f33a4e.sboyd@kernel.org>
From:   Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
In-Reply-To: <9367139a425dc7e4811c757b62f33a4e.sboyd@kernel.org>
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On 31/01/2023 00:30, Stephen Boyd wrote:
> Quoting Krzysztof Kozlowski (2023-01-26 01:31:55)
>> On 25/01/2023 21:44, Stephen Boyd wrote:
>>> Quoting Krzysztof Kozlowski (2023-01-23 01:49:25)
>>>> There is no point to allow selecting pin-controller drivers for Qualcomm
>>>
>>> pin controllers?
>>
>> Copy-paste, I'll fix it.
>>
>>>
>>>> ARMv7 SoCs when building ARM64 kernel, and vice versa.  This makes
>>>> kernel configuration more difficult as many do not remember the Qualcomm
>>>> SoCs model names/numbers.  There won't be a single image for ARMv7 and
>>>> ARMv8/9 SoCs, so no features/options are lost.
>>>
>>> Are the drivers used in arm32 emulation mode on these SoCs? I recall
>>> there are some SoCs they run with the arm architecture.
>>
>> I did not add it to the few SoCs which have upstream DTS in ARM and
>> ARM64. I added only to the ones which are in one specific folder. Also
>> my patch does not affect defconfigs (qcom_defconfig and arm64/defconfig).
> 
> Cool, thanks for checking. Is it possible to take a dtb from arm64 dts
> directory and boot it on an armv8 CPU running in 32-bit mode? Just
> wondering if even having the dts file exist in the arm64 architecture
> really matters here.

If DTSI (and/or board DTS) is in arm64, you still need DTS or a link in
arm directory. If such one is added, then the restrictions here can be
removed. Have in mind that I did the same already for pinctrl.


Best regards,
Krzysztof