RE: [EXT] Re: [PATCH v4 1/2] arm64: dts: imx8-ss-img: Assign slot for imx jpeg encoder/decoder

[Ming Qian]

>From: Krzysztof Kozlowski <krzysztof.kozlowski@xxxxxxxxxx>
>Sent: 2023年9月28日 13:03
>To: Ming Qian <ming.qian@xxxxxxx>; Mirela Rabulea (OSS)
><mirela.rabulea@xxxxxxxxxxx>; robh+dt@xxxxxxxxxx; shawnguo@xxxxxxxxxx
>Cc: krzysztof.kozlowski+dt@xxxxxxxxxx; conor+dt@xxxxxxxxxx;
>mchehab@xxxxxxxxxx; hverkuil-cisco@xxxxxxxxx; s.hauer@xxxxxxxxxxxxxx;
>kernel@xxxxxxxxxxxxxx; festevam@xxxxxxxxx; X.H. Bao
><xiahong.bao@xxxxxxx>; Eagle Zhou <eagle.zhou@xxxxxxx>; Tao Jiang
><tao.jiang_2@xxxxxxx>; dl-linux-imx <linux-imx@xxxxxxx>;
>devicetree@xxxxxxxxxxxxxxx; linux-media@xxxxxxxxxxxxxxx; linux-
>kernel@xxxxxxxxxxxxxxx; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
>Subject: Re: [EXT] Re: [PATCH v4 1/2] arm64: dts: imx8-ss-img: Assign slot for
>imx jpeg encoder/decoder
>
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>On 27/09/2023 11:19, Ming Qian wrote:
>>> From: Krzysztof Kozlowski <krzysztof.kozlowski@xxxxxxxxxx>
>>> Sent: 2023年9月27日 16:11
>>> To: Ming Qian <ming.qian@xxxxxxx>; Mirela Rabulea (OSS)
>>> <mirela.rabulea@xxxxxxxxxxx>; robh+dt@xxxxxxxxxx;
>shawnguo@xxxxxxxxxx
>>> Cc: krzysztof.kozlowski+dt@xxxxxxxxxx; conor+dt@xxxxxxxxxx;
>>> mchehab@xxxxxxxxxx; hverkuil-cisco@xxxxxxxxx; s.hauer@xxxxxxxxxxxxxx;
>>> kernel@xxxxxxxxxxxxxx; festevam@xxxxxxxxx; X.H. Bao
>>> <xiahong.bao@xxxxxxx>; Eagle Zhou <eagle.zhou@xxxxxxx>; Tao Jiang
>>> <tao.jiang_2@xxxxxxx>; dl-linux-imx <linux-imx@xxxxxxx>;
>>> devicetree@xxxxxxxxxxxxxxx; linux-media@xxxxxxxxxxxxxxx; linux-
>>> kernel@xxxxxxxxxxxxxxx; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
>>> Subject: [EXT] Re: [PATCH v4 1/2] arm64: dts: imx8-ss-img: Assign
>>> slot for imx jpeg encoder/decoder
>>>
>>> Caution: This is an external email. Please take care when clicking
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>>>
>>> On 26/09/2023 12:09, Ming Qian wrote:
>>>> There are total 4 slots available in the IP, and we only need to use
>>>> one slot in one os, assign a single slot for imx jpeg device node,
>>>> configure interrupt and power domain only for 1 slot, not for the all 4
>slots.
>>>
>>> DTS is independent of OS, so same DTS will be used by two OSes. This
>>> patch is not correct in that matter. Explanation is not proper justification.
>>>
>>
>> Hi Krzysztof,
>>
>> I agree that DTS is independent of OS, otherwise we need to choose the slot
>index by hard code in driver.
>> I think it's just the reason why we need this patch.
>> We have different platforms that use this IP, we need to configure the slot in
>dts.
>
>I still do not know what is the "slot". VM partitioning? Some pinmux
>configuration?
>
>Other platforms will use the same DTS, so the same slot and you are back at
>the same problem... DTS should be the full description of the hardware, thus
>removing interrupts is not "full description" anymore.
>

Hi Krzysztof,
    I have tried to explain the slot in the previous mail, although I'm not sure I made that clear. I think I need an example here. In our imx8q platform, we just want to assign slot 0 to linux, but in imx9 platform, we may want to assign slot 0 to linux, but slot 1 to a vm. So we don't want to enable power of slot 1 in linux.

Best regards,
Ming


>>
>> Would you please give some guide about proper justification?
>Describe architecture and then propose generic solution matching multiple
>vendors and IP blocks, not something solving only this one problem.
>
>Best regards,
>Krzysztof