Hi @ImHei!
From what I could understand, the operation frequencies are defined in the device tree. This is useful: https://community.nxp.com/t5/i-MX-Processors/Lower-CPU-Freq-in-imx8mp/m-p/1703005
You can see the definition of the frequencies here (line 134): imx8mp.dtsi « freescale « dts « boot « arm64 « arch - linux-toradex.git - Linux kernel for Apalis, Colibri and Verdin modules
As a test, I modified imx8mp.dtsi with the patch below, built the imx8mp-verdin-wifi-dev.dtb, and applied it on my Verdin iMX8MP Q 4GB WB IT V1.0B. Be aware that I don’t know if the values for opp-microvolt, opp-supported-hw, clock-latency-ns, and opp-suspend are correct! This was a simple quick test!
diff --git a/arch/arm64/boot/dts/freescale/imx8mp.dtsi b/arch/arm64/boot/dts/freescale/imx8mp.dtsi
index 9e0880992566..5627b5ff50df 100644
--- a/arch/arm64/boot/dts/freescale/imx8mp.dtsi
+++ b/arch/arm64/boot/dts/freescale/imx8mp.dtsi
@@ -135,29 +135,13 @@ a53_opp_table: opp-table {
compatible = "operating-points-v2";
opp-shared;
- opp-1200000000 {
- opp-hz = /bits/ 64 <1200000000>;
+ opp-1400000000 {
+ opp-hz = /bits/ 64 <1400000000>;
opp-microvolt = <850000>;
opp-supported-hw = <0x8a0>, <0x7>;
clock-latency-ns = <150000>;
opp-suspend;
};
-
- opp-1600000000 {
- opp-hz = /bits/ 64 <1600000000>;
- opp-microvolt = <950000>;
- opp-supported-hw = <0xa0>, <0x7>;
- clock-latency-ns = <150000>;
- opp-suspend;
- };
-
- opp-1800000000 {
- opp-hz = /bits/ 64 <1800000000>;
- opp-microvolt = <1000000>;
- opp-supported-hw = <0x20>, <0x3>;
- clock-latency-ns = <150000>;
- opp-suspend;
- };
};
memory@40000000 {
Upon the next boot, we can see that the frequency is the only one defined in the device tree:
root@verdin-imx8mp-06849036:~# cd /sys/devices/system/cpu/cpu0/cpufreq/
root@verdin-imx8mp-06849036:/sys/devices/system/cpu/cpu0/cpufreq# cat scaling_available_frequencies
1400000
root@verdin-imx8mp-06849036:/sys/devices/system/cpu/cpu0/cpufreq# cat scaling_cur_freq
1400000
For completeness, here is my tdx-info:
root@verdin-imx8mp-06849036:~# tdx-info
Software summary
------------------------------------------------------------
Bootloader: U-Boot
Kernel version: 5.15.129-6.4.0+git.67c3153d20ff #1 SMP PREEMPT Wed Sep 27 12:30:36 UTC 2023
Kernel command line: root=PARTUUID=298bca9d-02 ro rootwait console=tty1 console=ttymxc2,115200 consolebln
Distro name: NAME="TDX Wayland with XWayland"
Distro version: VERSION_ID=6.4.0-build.8
Hostname: verdin-imx8mp-06849036
------------------------------------------------------------
Hardware info
------------------------------------------------------------
HW model: Toradex Verdin iMX8M Plus WB on Verdin Development Board
Toradex version: 0058 V1.0B
Serial number: 06849036
Processor arch: aarch64
------------------------------------------------------------
In addition, I also recommend you take a look at the document i.MX Linux Reference Manual from NXP, which you can download from “Documentation” on this link: Embedded Linux for i.MX Applications Processors | NXP Semiconductors. To know which Documentation version you should download, please check the version of NXP release related to the Torizon/BSP from Toradex you are using in Embedded Linux Release Matrix | Toradex Developer Center.
Let us know if this helps you.
Best regards,
