Re: [PATCH 1/2] dt-bindings: remoteproc: xlnx: add auto boot feature

["Shah, Tanmay" <tanmays@amd.com>]

On 4/24/2026 11:53 AM, Krzysztof Kozlowski wrote:
> On 23/04/2026 19:59, Shah, Tanmay wrote:
>> Ack, I will rename it to xlnx,auto-boot.
>>
>>>>
>>>>>> +        type: boolean
>>>>>> +        description: remote core is either already running or ready to boot
>>>>>
>>>>> And why is this property of a board?
>>>>>
>>>>
>>>> Not sure what indicates it is? The property is under remoteproc child
>>>> device that is SOC level property. Remote core is on same SOC wher linux
>>>> core is running.
>>>
>>> So it is implied by SoC compatible? Please provide some arguments why it
>>> cannot be implied by the SoC compatible. I gave you one way out, but if
>>> you disagree then no problem.
>>>
>>
>> So on some SoC, the bootloader supports loading and starting of the
>> remote processor. But it is totally user's choice. User can choose to
>> load & start one core of a cluster via bootloader and leave another core
>> powered-off.
>> That is why it is not possible to decide based on SoC compatible.
> 
> OK. The problem is that "user" is a bit vague and usually user choice
> goes to user-space.
> 
> The property will be set or unset for ALL of given boards. So all of the
> DTS->DTB. That's why it should be clear why all such boards should
> behave like you described. If this is truly user, as in user-space,
> choice, then DT is not the way.
> 

Okay 'user' may not be the right choice of word. I should say 'hardware
configuration'. On same SoC, some cores can be configured to boot
automatically before Linux boots, and some won't. So if device-tree is
about hardware configuration, then we need a way to show which core is
configured to boot before linux. This configuration is board agnostic.
So I think auto-boot in device-tree makes sense.

The only advantage on this platform is, it has a way to detect if the
core is running or not runtime and don't have to rely on device-tree.

> 
>>
>> If we don't want to make it a device-tree property then I can implement
>> in a different way. New way will detect if the remote is running or not
>> via EMMI/SCMI call to the firmware, and take a decision based on that.
>> If this new way works, then I don't think we need auto-boot property at all.
>>
>> Let me know your thoughts.
> 
> This works for me and solves my questions from DT point of view, but I
> cannot judge whether this makes sense for you.
> 

I say I will keep it open ended for now. I will avoid introducing
auto-boot in the device-tree for now, and send a patch without it. In
future if for some other reason this property is needed, will send new
patch later.

Thanks,
Tanmay

> 
> Best regards,
> Krzysztof