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

[Peng Fan]

> Subject: Re: 回复: 回复: [EXT] Re: [PATCH v3 03/17] pinctrl: nxp: add
> SCMI pin control protocol driver
> 
> On 1/7/25 7:39 AM, Alice Guo (OSS) wrote:
> >> -----邮件原件-----
> >> 发件人: Marek Vasut <marex at denx.de>
> >> 发送时间: 2025年1月7日 4:46
> >> 收件人: Alice Guo (OSS) <alice.guo at oss.nxp.com>; Tom Rini
> >> <trini at konsulko.com>; Stefano Babic <sbabic at denx.de>; Fabio
> Estevam
> >> <festevam at gmail.com>; dl-uboot-imx <uboot-imx at nxp.com>;
> Lukasz
> >> Majewski <lukma at denx.de>; Sean Anderson
> <seanga2 at gmail.com>; Simon
> >> Glass <sjg at chromium.org>; Alper Nebi Yasak
> <alpernebiyasak at gmail.com>
> >> 抄送: u-boot at lists.denx.de; tharvey at gateworks.com; Peng Fan
> >> <peng.fan at nxp.com>; Ranjani Vaidyanathan
> >> <ranjani.vaidyanathan at nxp.com>; Ye Li <ye.li at nxp.com>
> >> 主题: Re: 回复: [EXT] Re: [PATCH v3 03/17] pinctrl: nxp: add SCMI
> pin
> >> control protocol driver
> >>
> >> On 1/6/25 10:56 AM, Alice Guo (OSS) wrote:
> >>>>> This patch provides a driver for the SCMI pin control protocol
> >>>>> which is based on ARM's System Control and Management
> Interface (SCMI) 3.2.
> >>>>> Currently, only the PINCTRL_CONFIG_SET command is
> implemented.
> >>>>
> >>>> What is the SCMI provider for this platform ?
> >>>
> >>> Hi Marek,
> >>>
> >>> System Manager which runs on M core sets pin or group
> configurations.
> >> U-Boot sends a SCMI message to System Manager to perform
> hardware
> >> operations. You can refer to the source code for details:
> >>
> https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2F
> github.com%2Fnxp-imx%2Fimx-
> sm&data=05%7C02%7Cpeng.fan%40nxp.com%7Cce165372497b40c20
> 3b408dd2f0df2fc%7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0%7C
> 0%7C638718459160955158%7CUnknown%7CTWFpbGZsb3d8eyJFbXB
> 0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoi
> TWFpbCIsIldUIjoyfQ%3D%3D%7C0%7C%7C%7C&sdata=LMKHHdAJpBC
> iaHbrVIw1fg9Y%2FbqC7mWOUDfan00gItw%3D&reserved=0.
> >>
> >> Can I use optee-os as a SCMI provider instead ?
> >
> > 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.

> 
> 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

You may configure TRDC to assign resources to A55, but
you still need to make sure M33 work proper.

Regards,
Peng.

That would surely make hardware
> bring up easier .