Re: 回复: 回复: [EXT] Re: [PATCH v3 03/17] pinctrl: nxp: add SCMI pin control protocol driver

[Marek Vasut]

On 1/7/25 1:11 PM, Peng Fan wrote:

[...]

>>> You cannot replace System Manager with optee-os.
>>
>> I think optee-os is also capable of being SCMI provider, so I have to
>> wonder, why does NXP use custom hand-written SCMI provider instead
>> of something already available, like that optee-os ?
> 
> System controller is the central controller of the system, and
> i.MX95 needs support safety.
> 
> We need to make sure when A55 crashes, safety core still work
> properly.

I think we are conflating two separate functionalities here:

- SM as the always-running monitor software
- SM as the SCMI provider

... please read on ...

>> And one more question, would it be possible to make U-Boot NOT
>> depend on SCMI at all and instead have regular clock/pinctrl drivers
>> which can configure the hardware using plain register writes, like it is
>> done on MX8M and older SoCs ?
> 
> See https://www.nxp.com/docs/en/data-sheet/IMX95CEC.pdf
> Only one boot mode:
> Low Power Boot (LPB): only M33 core is running after POR

OK

> You may configure TRDC to assign resources to A55, but
> you still need to make sure M33 work proper.
... so, I wonder, can the M33 act as SM, and can U-Boot configure 
whatever it needs via plain register writes, without having to rely on 
SCMI ?