Re: [PATCH 10/12] dt-bindings: ras: document estatus provider

[Ahmed Tiba <ahmed.tiba@arm.com>]

On 19/12/2025 10:53, Krzysztof Kozlowski wrote:
>> On 17/12/2025 12:41, Krzysztof Kozlowski wrote:
>>>> +properties:
>>>> +  compatible:
>>>> +    const: arm,ras-ffh
>>>
>>> Again ras - what's that? Your patch or binding must explain that.
>>
>> That updated description will explicitly expand the Arm RAS acronym so the
>> compatible string is self-explanatory.
>>
>>>> +
>>>> +  reg:
>>>> +    minItems: 1
>>>
>>> Why is this flexible?
>>
>> I'll keep `reg` describing the CPER status buffer, cap it at two entries, and
>> document the second entry as the optional doorbell register that some firmware
>> requires before reusing the buffer.
>
> I still do not understand why this is flexible or in other words - why
> second address space appears and disappears.

The second address space is only present for firmware that exposes an ACK register.
Not all platforms require this extra handshake so that address shows up only
when the extra handshake exists. I’ll say that clearly in the binding
so it’s obvious the region is optional.

>>
>>>> +    items:
>>>> +      - description: CPER status block exposed by firmware
>>>> +      - description:
>>>> +          Optional 32- or 64-bit acknowledgment register. Firmware watches this
>>>> +          register and expects bit 0 to be written to 1 once the OS consumes the
>>>> +          status buffer so it can reuse the record.
>>>> +


Best regards,
Ahmed