How to disable/control M7 cpu on i.MX8MP?

NXP i.MX8M Plus
1

We want to optimize power consumption and as we don’t use M7 cpu at the moment we want to disable it.
Which steps do we need to take?

2

By default the core should be held in WFI mode until it is initialized and firmware is uploaded to it. However you can control it through NXP’s SMCCC calls from u-boot.

arm_smccc_smc(IMX_SIP_SRC, IMX_SIP_SRC_M4_STOP, 0, 0, 0, 0, 0, 0, &res);

3

When running command from u-boot I get the following error:

Hit any key to stop autoboot:  0
u-boot=> arm_smccc_smc(IMX_SIP_SRC, IMX_SIP_SRC_M4_STOP, 0, 0, 0, 0, 0, 0, &res);
syntax error
4

that isn’t a command. There is no user interface for this, it would need to be incorporated into the u-boot code.