• State TI Thinks Resolved
  • Locked Locked
  • Replies 3 replies
  • Answers 1 answer
  • Subscribers 98 subscribers
  • Views 471 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

Linux/AM3352: Setting MPU frequency to 300MHz

Paul.Wu
Intellectual 360 points

Part Number: AM3352

Tool/software: Linux

Hi,

 In  the uboot src, I add freq=MPUPLL_M_300 in the func  get_dpll_mpu_params, there is no  effective.

Maybe I need to change in the kernel , please help me. 

Thank you.

  • 0
    TI__Guru**** 170625 points
    Hi Paul,

    Do you use AM335x TI PSDK Linux v5.02 (kernel v4.14.79)?

    Do yo use AM335x TI board (EVM, SK, ICE, BBB) or custom board?

    How do you verify/check what frequency you have for the Cortex-A8 MPU core?

    Make sure you are aligned with below user guides:

    software-dl.ti.com/.../Foundational_Components_Kernel_Drivers.html
    software-dl.ti.com/.../Examples_and_Demos_Sub-system_Demos.html

    www.ti.com/.../sprac74a.pdf

    Regards,
    Pavel
  • 0 in reply to Pavel Botev
    Intellectual 360 points
    I use TI SDK 5.0.0.15(kenel v4.14.40) and am3352 evm but no PMIC.
    There is no scaling_setspeed cmd in the filesystem.

    Linux am335x-evm 4.14.40-g4796173fc5 #1 PREEMPT Wed Feb 27 05:53:42 PST 2019 armv7l GNU/Linux

    root@am335x-evm:~# cat /proc/cpuinfo
    processor : 0
    model name : ARMv7 Processor rev 2 (v7l)
    BogoMIPS : 597.60
    Features : half thumb fastmult vfp edsp neon vfpv3 tls vfpd32
    CPU implementer : 0x41
    CPU architecture: 7
    CPU variant : 0x3
    CPU part : 0xc08
    CPU revision : 2

    Hardware : Generic AM33XX (Flattened Device Tree)
    Revision : 0000
    Serial : 0000000000000000

    root@am335x-evm:~# ls -l /sys/devices/system/cpu/cpu0/
    drwxr-xr-x 5 root root 0 Oct 6 04:17 cpuidle
    -r-------- 1 root root 4096 Oct 6 04:17 crash_notes
    -r-------- 1 root root 4096 Oct 6 04:17 crash_notes_size
    lrwxrwxrwx 1 root root 0 Oct 6 04:17 of_node -> ../../../../firmware/devicetree/base/cpus/cpu@0
    drwxr-xr-x 2 root root 0 Oct 6 04:17 power
    lrwxrwxrwx 1 root root 0 Oct 6 01:53 subsystem -> ../../../../bus/cpu
    drwxr-xr-x 2 root root 0 Oct 6 04:17 topology
    -rw-r--r-- 1 root root 4096 Oct 6 01:53 uevent


    -sh: /sys/devices/system/cpu/cpu0/cpufreq/scaling_setspeed: No such file or directory
  • 0 in reply to Paul.Wu
    TI__Guru**** 170625 points
    Paul,

    Let we switch to u-boot for a while.

    When you modify get_dpll_mpu_params() function to support only MPUPLL_M_300, can you then check if MPU DPLL settings are applied correctly? You can stop the boot flow at the u-boot prompt and dump the MPU DPLL registers to check what frequency you have in u-boot.

    Then at userspace, you can also dump MPU DPLL registers to check what frequency you have, you can use devmem2 or omapconf tool.

    With omapconf tool, you can also run below command to check what frequency you have for the MPU Cortex-A8:

    root@am335x-evm:~# omapconf show opp
    root@am335x-evm:~# omapconf dump dpll mpu
    root@am335x-evm:~# omapconf show dpll

    Regards,
    Pavel