topic [imx8mm][Linux] Missing CPU frequency in i.MX Processors

[imx8mm][Linux] Missing CPU frequency

Nonifier — Thu, 27 May 2021 14:36:24 GMT

Hi guys,

According to your linux user guide documentation : https://www.nxp.com/docs/en/user-guide/IMX_LINUX_USERS_GUIDE.pdf#_OPENTOPIC_TOC_PROCESSING_d672e10126.

To check the maximum frequency:
cat /sys/devices/system/cpu/*/cpufreq/cpuinfo_max_freq

On my running IM8MM board, none of those 'cpufreq' folders exist :

imx8mmevk:~$ ls /sys/devices/system/cpu/cpu*/cpufreq/*
ls: cannot access '/sys/devices/system/cpu/cpu*/cpufreq/*': No such file or directory

Also, '/proc/cpuinfo' does not report any CPU frequency either :

imx8mmevk:~$ cat /proc/cpuinfo 
processor : 0
BogoMIPS : 16.00
Features : fp asimd evtstrm aes pmull sha1 sha2 crc32 cpuid
CPU implementer : 0x41
CPU architecture: 8
CPU variant : 0x0
CPU part : 0xd03
CPU revision : 4

processor : 1
BogoMIPS : 16.00
Features : fp asimd evtstrm aes pmull sha1 sha2 crc32 cpuid
CPU implementer : 0x41
CPU architecture: 8
CPU variant : 0x0
CPU part : 0xd03
CPU revision : 4

processor : 2
BogoMIPS : 16.00
Features : fp asimd evtstrm aes pmull sha1 sha2 crc32 cpuid
CPU implementer : 0x41
CPU architecture: 8
CPU variant : 0x0
CPU part : 0xd03
CPU revision : 4

processor : 3
BogoMIPS : 16.00
Features : fp asimd evtstrm aes pmull sha1 sha2 crc32 cpuid
CPU implementer : 0x41
CPU architecture: 8
CPU variant : 0x0
CPU part : 0xd03
CPU revision : 4

The image I'm using has been built using Yocto :

Version : imx-linux-gatesgarth
Documentation : https://source.codeaurora.org/external/imx/imx-manifest/tree/README?h=imx-linux-gatesgarth

repo init -u https://source.codeaurora.org/external/imx/imx-manifest -b imx-linux-gatesgarth -m imx-5.10.9-1.0.0.xml
repo sync
MACHINE=imx8mmevk DISTRO=fsl-imx-xwayland source ./imx-setup-release.sh -b bld-xwayland
bitbake imx-image-full

Is there anything special that needs to be done to enable cpu frequency reporting working properly ? Did I do something wrong ?

Thanks for your help.

Olivier.

Re: [imx8mm][Linux] Missing CPU frequency

igorpadykov — Fri, 28 May 2021 00:26:19 GMT

Hi Olivier

one can check cpufreq linux kernel configuration described in sect.2.5.3.4 Menu Configuration Options

i.MX Linux User’s Guide

https://www.nxp.com/design/software/embedded-software/i-mx-software/embedded-linux-for-i-mx-applications-processors:IMXLINUX?tab=In-Depth_Tab

Best regards
igor

Re: [imx8mm][Linux] Missing CPU frequency

Nonifier — Fri, 28 May 2021 07:57:17 GMT

Hi @igorpadykov

Thanks for the quick reply.

The file you're referring to (/sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq) is missing from my image. That's my original point

None of the /cpufreq/ folder is present on my image. Do I need any Yocto configuration/step/recipe to have those /cpufreq/ kernel files configured in my image ?

Best,

Olivier.

Re: [imx8mm][Linux] Missing CPU frequency

igorpadykov — Fri, 28 May 2021 10:15:41 GMT

could you try to reproduce issue on NXP EVK reference board.

Best regards
igor

Re: [imx8mm][Linux] Missing CPU frequency

Nonifier — Fri, 28 May 2021 10:48:14 GMT

Hi @igorpadykov

I'm experiencing the issue on a i.MX8M Mini Evaluation Kit

https://www.nxp.com/design/development-boards/i-mx-evaluation-and-development-boards/evaluation-kit-for-the-i-mx-8m-mini-applications-processor:8MMINILPD4-EVK

Not sure if this is considered as a "EVK reference board".

Best,

Olivier.

Re: [imx8mm][Linux] Missing CPU frequency

Nonifier — Fri, 04 Jun 2021 12:23:32 GMT

Any update on this by any chance ?

Thanks a lot,

Olivier.