SP_MIN for V4.0.0

[fpoussin]

I've just made the switch for V4.0.0 (A-TF 2.6, Linux 5.15 but with Barebox instead of U-Boot) using Buildroot as before.

I had trouble to bring the system up because of what has been changed in regard to SCMI.

The DT node's compatible name was changed to force OP-TEE, which is a no go in my case for now.

I'll just leave the solution here in case anyone faces the same issue.

Simply override the scmi node with the old values:

&scmi {
    // Revert OP-TEE to SP_MIN
    // Previously compatible = "linaro,scmi-optee";
    compatible = "arm,scmi-smc";
    arm,smc-id = <0x82002000>;
};

This will allow you to boot without any changes compared to V3.

[Bernard PUEL]

fyi, buildroot V4.0.0 porting was delivered here: https://github.com/bootlin/buildroot-external-st/tree/openstlinux-5.15-buildroot-2022.02-mp1-v22.06.15

[Erwan SZYMANSKI]

Hello @fpoussin​,

Thank you for your contribution. You are right, since the v4.0, the default secure monitor is now OP-TEE and not SP_MIN.

By the way, ST highly recommends to use OP-TEE on this OSTL version and on next ones.

Kind regards,

Erwan.

[LionelD]

Hello @fpoussin​ ,

One more question, I'm surprised you need to patch the scmi node because, in order to ease the usage of SP-MIN for some customer that want to stay (for now) on SP-MIN, we directly patch the scmi node from SP-MIN (the u-boot DT node) that allow to dynamically switch to arm,scmi-smc compatible. U-Boot do it dynamically between U-Boot DT and the kernel one.

Are you sure to use all the V4.0 firmware version?