Re: [PATCH 2/4] dt-bindings: memory: mediatek: Add smi-sub-common property for reset

[AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>]

Il 24/10/24 03:28, Friday Yang (杨阳) ha scritto:
> On Wed, 2024-08-21 at 10:55 +0200, Krzysztof Kozlowski wrote:
>>   	
>> External email : Please do not click links or open attachments until
>> you have verified the sender or the content.
>>   On 21/08/2024 10:26, friday.yang wrote:
>>> On the MediaTek platform, some SMI LARBs are directly linked to SMI
>>> common. While some SMI LARBs are linked to SMI sub common, then SMI
>>> sub common is linked to SMI common. Add 'mediatek,smi-sub-comm' and
>>> 'mediatek,smi-sub-comm-in-portid' properties here. The SMI reset
>>> driver could query which port of the SMI sub common the current
>> LARB
>>> is linked to through the two properties. The hardware block diagram
>>> could be described as below.
>>>
>>>               SMI Common(Smart Multimedia Interface Common)
>>>                   |
>>>           +----------------+-------
>>>           |                |
>>>           |                |
>>>           |                |
>>>           |                |
>>>           |                |
>>>         larb0       SMI Sub Common
>>>                     |      |     |
>>>                    larb1  larb2 larb3
>>>
>>> Signed-off-by: friday.yang <friday.yang@mediatek.com>
>>> ---
>>>   .../mediatek,smi-common.yaml                  |  2 ++
>>>   .../memory-controllers/mediatek,smi-larb.yaml | 22
>> +++++++++++++++++++
>>>   2 files changed, 24 insertions(+)
>>>
>>> diff --git a/Documentation/devicetree/bindings/memory-
>> controllers/mediatek,smi-common.yaml
>> b/Documentation/devicetree/bindings/memory-controllers/mediatek,smi-
>> common.yaml
>>> index 2f36ac23604c..4392d349878c 100644
>>> --- a/Documentation/devicetree/bindings/memory-
>> controllers/mediatek,smi-common.yaml
>>> +++ b/Documentation/devicetree/bindings/memory-
>> controllers/mediatek,smi-common.yaml
>>> @@ -39,6 +39,7 @@ properties:
>>>             - mediatek,mt8186-smi-common
>>>             - mediatek,mt8188-smi-common-vdo
>>>             - mediatek,mt8188-smi-common-vpp
>>> +          - mediatek,mt8188-smi-sub-common
>>>             - mediatek,mt8192-smi-common
>>>             - mediatek,mt8195-smi-common-vdo
>>>             - mediatek,mt8195-smi-common-vpp
>>> @@ -107,6 +108,7 @@ allOf:
>>>           compatible:
>>>             contains:
>>>               enum:
>>> +              - mediatek,mt8188-smi-sub-common
>>>                 - mediatek,mt8195-smi-sub-common
>>>       then:
>>>         required:
>>> diff --git a/Documentation/devicetree/bindings/memory-
>> controllers/mediatek,smi-larb.yaml
>> b/Documentation/devicetree/bindings/memory-controllers/mediatek,smi-
>> larb.yaml
>>> index 2381660b324c..5f162bb360db 100644
>>> --- a/Documentation/devicetree/bindings/memory-
>> controllers/mediatek,smi-larb.yaml
>>> +++ b/Documentation/devicetree/bindings/memory-
>> controllers/mediatek,smi-larb.yaml
>>> @@ -69,6 +69,16 @@ properties:
>>>       description: the hardware id of this larb. It's only required
>> when this
>>>         hardware id is not consecutive from its M4U point of view.
>>>   
>>> +  mediatek,smi-sub-comm:
>>> +    $ref: /schemas/types.yaml#/definitions/phandle
>>> +    description: a phandle of smi_sub_common that the larb is
>> linked to.
>>
>> Why do you have to smi phandle properties per each node?
>>
> 
> As shown in the picture from the commit message, we have multipule smi-
> sub-common, each SMI larb may link to one of the smi-sub-common. So we
> need the 'mediatek,smi-sub-comm' to describe which smi-sub-common the
> larb is linked to.
> In next version, I will add two smi-sub-common to the diagram in the
> commit message.
> 
>>> +
>>> +  mediatek,smi-sub-comm-in-portid:
>>> +    $ref: /schemas/types.yaml#/definitions/uint32
>>> +    minimum: 0
>>> +    maximum: 7
>>> +    description: which port of smi_sub_common that the larb is
>> linked to.
>>
>> Merge it into phandle.
>>
> 
> Just confirm,
> Do you mean merge these two into one property, like:
> mediatek,smi-sub-comm = <&phandle port-id>;
> 
>>> +
>>>   required:
>>>     - compatible
>>>     - reg
>>> @@ -125,6 +135,18 @@ allOf:
>>>         required:
>>>           - mediatek,larb-id
>>>   
>>> +  - if:
>>> +      properties:
>>> +        compatible:
>>> +          contains:
>>> +            enum:
>>> +              - mediatek,mt8188-smi-larb
>>> +
>>> +    then:
>>> +      required:
>>> +        - mediatek,smi-sub-comm
>>> +        - mediatek,smi-sub-comm-in-portid
>>> +
>>
>> and add it to the example (since you claim it is valid for every
>> device).
>>

It's valid only for the Local Arbiters that have a sub-common port, which anyway
are only the ones that are used by CAMSYS if I'm not wrong....

Regardless of that, not all of the mt8188-smi-larb *require* smi-sub-comm.

Besides, if the larb is anyway already linked to a sub-common, can't we just grab
that from walking back?
Or is this property's purpose to actually add a link to a sub-common?

Regards,
Angelo

> 
> OK, I will add this to the example.
> 
>> Best regards,
>> Krzysztof
>>