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

[Peng Fan]

On Tue, Jan 07, 2025 at 01:37:06PM +0100, Marek Vasut wrote:
>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 ?

Technically yes for prototype building, except TRDC and other secure periphrals.

Regards,
Peng