Re: [PATCH v3 1/2] dt-bindings: soc: qcom: Add qcom,kaanapali-imem compatible

[Aiqun(Maria) Yu]

On 11/11/2025 4:29 PM, Kathiravan Thirumoorthy wrote:
> 
> On 11/7/2025 1:54 AM, Bjorn Andersson wrote:
>> On Tue, Nov 04, 2025 at 03:58:27PM +0100, Konrad Dybcio wrote:
>>> On 11/4/25 3:52 PM, Krzysztof Kozlowski wrote:
>>>> On 04/11/2025 15:38, Konrad Dybcio wrote:
>>>>> On 11/4/25 3:37 PM, Krzysztof Kozlowski wrote:
>>>>>> On 04/11/2025 15:35, Konrad Dybcio wrote:
>>>>>>> On 11/4/25 3:26 PM, Krzysztof Kozlowski wrote:
>>>>>>>> This I got, but nothing here explains why you need generic
>>>>>>>> compatible.
>>>>>>>> To re-iterate: there was no generic compatible before, now there
>>>>>>>> is.
>>>>>>>> Writing bindings and numerous reviews from DT maintainers ask
>>>>>>>> not to use
>>>>>>>> generic compatibles.
>>>>>>> OK so let's not worry about a generic compatible. IMEM exists since
>>>>>>> MSM8974 and it only had major hw updates with SM8550. They don't
>>>>>>> impact the software interface though, so qcom,msm8974-imem is OK.
>>>>>>>
>>>>>>> There's a separate control/status register address space for each
>>>>>>> instance of this IP (usually far apart from the actual SRAM pool),
>>>>>>> which Linux doesn't have to care about.
>>>>>> Just use qcom,kaanapali-imem - that's the first device here
>>>>>> without syscons.
>>>>> So we don't want to move the existing ones over?
>>>> This was never discussed and this patch did not do it. You cannot move
>>>> them, that's ABI.
>>> I see, I implicitly assumed this would be a sweeping change.
>>>
>>> So should the Kaanapali submitters simply send a version of this
>>> patch with:
>>>
>>> - oneOf:
>>>    - const: qcom,kaanapali-imem
>>>    - items:
>>>      # existing big list
>>>
>>> ?
>> We have 33 cases of "this is just a generic Qualcomm IMEM block", could
>> we just make it "qcom,imem" until there's actually a sign that it's not
>> a platform-independent block?

If it’s not platform-specific, why not use a common compatible here? I
mean let's have a common "qcom,imem" start from kaanapali.

What benefits would a platform-specific approach bring in this case? For
newer platforms, we could simply adopt the common compatible and avoid
adding a dedicated platform compatible name.

Also, the old bootloader reboot-mode solution that uses the IMEM area as
a magic syscon is deprecated for newer targets.

> 
> 
> Any conclusion / further feedback on this would be helpful to move
> things forward. Thanks in advance.


Which platform are you waiting for as a reference? Or are you only
focused on the current Kaanapali?
By the way, great to see we share the same goal here.

> 
> 
>>
>> Regards,
>> Bjorn
>>
>>> I'm not a huge fan of using kaanapali as the fallback-going-forward
>>> since it's literally the newest platform on the shelves (or perhaps
>>> not even on the shelves yet..) so it's going to look funny when
>>> someone comes up with support for another 2013 soc.. but perhaps
>>> that's just how things are supposed to be
>>>
>>> Konrad


-- 
Thx and BRs,
Aiqun(Maria) Yu