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AM5728: OPP during boot

Bob Engineer 2
Intellectual 530 points
Part Number: AM5728

Hi,

could you tell me please which OPP is used during kernel boot, and whether it is possible to control this?

Thanks and best regards,

Bob.

  • 0
    TI__Guru**** 162770 points

    Hi Bob,

    I assume that you are asking about MPU. The MPU Boots at OPP Nominal. However in kernel
    you can always change the OPP by changing the cpufreq governor to userspace.

    Once you boot to kernel:

    echo userspace > /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor

    Then:

    cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequencies

    will give you the available frequencies.

    You can pick one of them say 'x' then:

    echo x > /sys/devices/system/cpu/cpu0/cpufreq/scaling_setspeed

    This changes the OPP as per your need.

    Best Regards,
    Keerthy

  • 0 in reply to Keerthy J
    Intellectual 530 points

    Hi Keerthy,

    Thanks.  What I would really like is for the kernel to boot using the maximum clock frequency (opp_high I guess).  Is that possible?

    Then once booted, I can then use the technique you describe to adjust the frequency as needed for the application.

    Best regards,

    Bob.

  • 0 in reply to Bob Engineer 2
    TI__Guru**** 162770 points

    Hi Bob,

    There is an FAQ on the older version of u-boot: 

    Let me know if that helps you.

    Best Regards,
    Keerthy