How do i get cpu frequency in imx8mm?

[takeshi100]

Hi.

I can't get cpu frequency on imx8mm with /proc/cpuinfo etc.

How do i get it?

■conditions
BSP = i.MX Linux Yocto Project BSP 6.1.55_2.2.0
image =   image based core-image-full-cmdline-imx8mm-lpddr4-evk
hardware = custom board with imx8mm

■log(cpu info)

root@XXX:~# cpufreq-info

cpufrequtils 008: cpufreq-info (C) Dominik Brodowski 2004-2009

Report errors and bugs to cpufreq@vger.kernel.org, please.

analyzing CPU 0:

  no or unknown cpufreq driver is active on this CPU

analyzing CPU 1:

  no or unknown cpufreq driver is active on this CPU

analyzing CPU 2:

  no or unknown cpufreq driver is active on this CPU

analyzing CPU 3:

  no or unknown cpufreq driver is active on this CPU

root@XXX:~# 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

root@XXX:~# lscpu

Architecture:            aarch64

  CPU op-mode(s):        32-bit, 64-bit

  Byte Order:            Little Endian

CPU(s):                  4

  On-line CPU(s) list:   0-3

Vendor ID:               ARM

  Model name:            Cortex-A53

    Model:               4

    Thread(s) per core:  1

    Core(s) per cluster: 4

    Socket(s):           -

    Cluster(s):          1

    Stepping:            r0p4

    BogoMIPS:            16.00

    Flags:               fp asimd evtstrm aes pmull sha1 sha2 crc32 cpuid

Caches (sum of all):

  L1d:                   128 KiB (4 instances)

  L1i:                   128 KiB (4 instances)

  L2:                    512 KiB (1 instance)

NUMA:

  NUMA node(s):          1

  NUMA node0 CPU(s):     0-3

Vulnerabilities:

  Gather data sampling:  Not affected

  Itlb multihit:         Not affected

  L1tf:                  Not affected

  Mds:                   Not affected

  Meltdown:              Not affected

  Mmio stale data:       Not affected

  Retbleed:              Not affected

  Spec rstack overflow:  Not affected

  Spec store bypass:     Not affected

  Spectre v1:            Mitigation; __user pointer sanitization

  Spectre v2:            Not affected

  Srbds:                 Not affected

  Tsx async abort:       Not affected

■log(kernel config)

root@XXX:~# zcat /proc/config.gz | grep CPU_FREQ

CONFIG_CPU_FREQ=y

CONFIG_CPU_FREQ_GOV_ATTR_SET=y

CONFIG_CPU_FREQ_GOV_COMMON=y

CONFIG_CPU_FREQ_STAT=y

# CONFIG_CPU_FREQ_DEFAULT_GOV_PERFORMANCE is not set

# CONFIG_CPU_FREQ_DEFAULT_GOV_POWERSAVE is not set

# CONFIG_CPU_FREQ_DEFAULT_GOV_USERSPACE is not set

CONFIG_CPU_FREQ_DEFAULT_GOV_ONDEMAND=y

# CONFIG_CPU_FREQ_DEFAULT_GOV_CONSERVATIVE is not set

# CONFIG_CPU_FREQ_DEFAULT_GOV_SCHEDUTIL is not set

CONFIG_CPU_FREQ_GOV_PERFORMANCE=y

CONFIG_CPU_FREQ_GOV_POWERSAVE=y

CONFIG_CPU_FREQ_GOV_USERSPACE=y

CONFIG_CPU_FREQ_GOV_ONDEMAND=y

CONFIG_CPU_FREQ_GOV_CONSERVATIVE=y

CONFIG_CPU_FREQ_GOV_SCHEDUTIL=y

CONFIG_CPU_FREQ_THERMAL=y

root@XXX:~# zcat /proc/config.gz | grep CPUFREQ
CONFIG_CPUFREQ_DT=y
CONFIG_CPUFREQ_DT_PLATDEV=y
CONFIG_ACPI_CPPC_CPUFREQ=m
CONFIG_ACPI_CPPC_CPUFREQ_FIE=y
CONFIG_ARM_SCPI_CPUFREQ=y
CONFIG_ARM_IMX_CPUFREQ_DT=y
CONFIG_ARM_SCMI_CPUFREQ=y
CONFIG_QORIQ_CPUFREQ=y

[Chavira]

Hi @takeshi100!

Thank you for contacting NXP Support!

The command should be:

cat /sys/devices/system/cpu/*/cpufreq/cpuinfo_cur_freq

You can see all the available options in our Linux User Guide on chapter "6.2 CPU frequency scaling"

https://www.nxp.com/docs/en/user-guide/IMX_LINUX_USERS_GUIDE.pdf

Best Regards!

Chavira

[takeshi100]

Hi, Chavira.

Thanks for replying.

There aren't cpufreq directories.
Is there anything I need to configure?

■log

root@XXX:~# ls /sys/devices/system/cpu/cpu0/
cache cpu_capacity cpuidle crash_notes crash_notes_size hotplug node0 of_node online power regs subsystem topology uevent

Best Regards.

[takeshi100 · Accepted solution]

I resolved this problem by fixing device tree.

Pending of cpufreq-dt was happend.
The cause of it was incorrect configuration of the PMIC in device tree.
The PMIC of the custom board and evk are different, and the I2C line to which they belong is also different.

■log
root@XXX:~# journalctl -b | grep cpufreq
Mar 03 09:49:19 XXX kernel: imx-cpufreq-dt imx-cpufreq-dt: cpu speed grade 3 mkt segment 0 supported-hw 0x8 0x1
Mar 03 11:38:17 XXX kernel: platform cpufreq-dt: deferred probe pending

■reference
・https://www.reddit.com/r/linux4noobs/comments/1brkjja/trying_to_get_cpufreqdt_functioning_on_arm/
・https://community.nxp.com/t5/i-MX-Processors/How-to-enable-cpufreq-in-Linux-imx8mmevk-5-10-35-lts-Ha...