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DM8148 ARM OPP change with Linux PSP-04.01.00.07

Se-Joong Lee
Prodigy 40 points

Hi,

I downloaded PSP-04.01.00.07, which seems to have enabled CPUFreq Framework, thus, we can change OPP of ARM.

The ChangeLog file says OPP50 and OPP120 are temporarily disabled due to system instability on some boards.

I want to use those OPPs at my own risk. So, I changed  the arch/arm/mach-omap2/opp814x_data.c  as directed in the ChangeLog.

However, it seems that the the default configuration that I'm using does not build opp814x_data.c file.

I also tried to pass the option, CONFIG_PM_OPP=y, and it leads to a error message saying 'redefinition' of many opp related files...

Please give me some help on this issue.

Thanks.

Regards,

Se-Joong

  • 0
    TI__Expert 4230 points

    Hello Se-Joong,

    There is a forum for linux relaed queries.In future please post there .

    http://e2e.ti.com/support/embedded/linux/default.aspx

    To enable CPUFreq, please do the following:

     Enable CpuFrequency scaling and slect governors from CPU power management option as shown below:

    CPU Power Management  ---> 

    [*] CPU Frequency scaling                                                                                                     

      │ │                                                          [ ]   Enable CPUfreq debugging (NEW)                                                                                            │ │

      │ │                                                          <*>   CPU frequency translation statistics (NEW)                                                                                │ │

      │ │                                                          [ ]     CPU frequency translation statistics details (NEW)                                                                      │ │

      │ │                                                                Default CPUFreq governor (performance)  --->                                                                              │ │

      │ │                                                          -*-   'performance' governor                                                                                                    │ │

      │ │                                                          < >   'powersave' governor (NEW)                                                                                                │ │

      │ │                                                          <* >   'userspace' governor for userspace frequency scaling (NEW)                                                                │ │

      │ │                                                          < >   'ondemand' cpufreq policy governor (NEW)                                                                                  │ │

      │ │                                                          < >   'conservative' cpufreq governor (NEW)                                                                                     │ │

      │ │                                                          [ ] CPU idle PM support                                            

     

    2.  Enable Architecture support and OPP Library

     Power management options  --->

    -*- Power Management support                                                                                                    │ │

      │ │                                                          [*]   Power Management Debug Support                                                                                            │ │

      │ │                                                          [ ]     Extra PM attributes in sysfs for low-level debugging/testing                                                            │ │

      │ │                                                          [*]     Verbose Power Management debugging                                                                                      │ │

      │ │                                                          [*] Suspend to RAM and standby                                                                                                  │ │

      │ │                                                          [ ]   Test suspend/resume and wakealarm during bootup                                                                           │ │

      │ │                                                          < > Advanced Power Management Emulation                                                                                         │ │

      │ │                                                          -*- Run-time PM core functionality                                                                                              │ │

      │ │                                                          [*] Architecure Supports multiple OPPs                                                                                          │ │

      │ │                                                          [*]   Operating Performance Point (OPP) Layer library  

     

    Enable the OPPs you want to use in opp814x_data.c. re-build the kernel.

    This is som how slipped from the user guide http://processors.wiki.ti.com/index.php/TI81XX_PSP_PM_DVFS_User_Guide.

     We will update the user guide with this info.

    Regards,

    RK

  • 0 in reply to Ravikumar Kattekola
    Prodigy 170 points

    HI Ravikumar,

    I have tried your above suggestion with psp04.04.00.01, but when I try to access the sysfs files, I get a kernel exception in cpufreq_cpu_get(), followed by the spinlock of that function being hung.  This is using the ti8148evm board.  I don't see any relevant changes in the October kernel release for the DM8148.  Am I missing something?

    Regards,

    Dave