IMX93 power management

[romulus]

I'm conducting power management investigations and tests on an IMX93 development board.

The IMX93 has two processors: an Arm Cortex-A55 and an Arm Cortex-M33.

Current Situation:

When I input the reboot command through the A55's serial port (USB-Enhanced-SERIAL-A-CH342), both the A55 and M33 restart.

Desired Behavior:

I want to modify this so that when I input the reboot command through the A55's serial port (USB-Enhanced-SERIAL-A-CH342), only the A55 restarts, while the M33 continues to operate normally.

Problem:

I haven't been able to locate the necessary configuration settings to achieve this.

Question:

Could you please advise on where I can modify the system to achieve this desired behavior?

Thank you very much.

[joanxie]

normally when A core and M core go to DSM, we wake up M core and put A core in the DSM, because M core has fast response and lower power consumption, since you need wake up A core, you can refer to the AN as below

i.MX 8M Low Power Design By M Core Running In System Suspend

find the example  code to wake up the A core and notify the M core in Suspend mode are added in ATF of chapter 5.5.2 Use GIR for wake-up and notification

[romulus]

Thank you very much for your answer.

The document you provided is about the i.MX8M.

To confirm, is the handling method for the i.MX93 the same as for the i.MX8M?

[joanxie]

for imx93, when you put imx93 M core and A core to suspend mode, you can wake up A core only, one can download imx93 SDK, find the demo named "power mode switch", then use "echo mem>/sys/power/state" to set A core to suspend mode, and use power mode switch like this to set M core to suspend mode

joanxie_0-1736814432828.png

then you can just use mouse or keyboard to wake up A core only

[romulus]

I'll try it right away.
Thank you very much.