Busfreq OPTEE set from 24000000 to 400000000 start.

[layleon]

There is a lot of this information that will always be displayed periodically, why? How to mute it? Can I only modify the source code without printk? 

[  206.247131] Busfreq OPTEE set from 400000000 to 24000000 start...
[  206.255946] Busfreq OPTEE set to 24000000 done! cpu=0
[  206.295989]
[  206.295989] Busfreq OPTEE set from 24000000 to 400000000 start...
[  206.332122] Busfreq OPTEE set to 400000000 done! cpu=0
[  209.447133]
[  209.447133] Busfreq OPTEE set from 400000000 to 24000000 start...
[  209.455924] Busfreq OPTEE set to 24000000 done! cpu=0
[  209.496017]
[  209.496017] Busfreq OPTEE set from 24000000 to 400000000 start...
[  209.532123] Busfreq OPTEE set to 400000000 done! cpu=0
[  212.647100]
[  212.647100] Busfreq OPTEE set from 400000000 to 24000000 start...
[  212.655921] Busfreq OPTEE set to 24000000 done! cpu=0
[  212.696172]
[  212.696172] Busfreq OPTEE set from 24000000 to 400000000 start...
[  212.732340] Busfreq OPTEE set to 400000000 done! cpu=0
[  215.847153]
[  215.847153] Busfreq OPTEE set from 400000000 to 24000000 start...
[  215.855952] Busfreq OPTEE set to 24000000 done! cpu=0
[  215.895905]
[  215.895905] Busfreq OPTEE set from 24000000 to 400000000 start...
[  215.931981] Busfreq OPTEE set to 400000000 done! cpu=0
[  219.047116]
[  219.047116] Busfreq OPTEE set from 400000000 to 24000000 start...
[  219.055954] Busfreq OPTEE set to 24000000 done! cpu=0
[  219.115985]
[  219.115985] Busfreq OPTEE set from 24000000 to 400000000 start...
[  219.141949] Busfreq OPTEE set to 400000000 done! cpu=0
[  222.727073]
[  222.727073] Busfreq OPTEE set from 400000000 to 24000000 start...
[  222.735873] Busfreq OPTEE set to 24000000 done! cpu=0
[  222.775976]
[  222.775976] Busfreq OPTEE set from 24000000 to 400000000 start...
[  222.812075] Busfreq OPTEE set to 400000000 done! cpu=0
[  225.927155]
[  225.927155] Busfreq OPTEE set from 400000000 to 24000000 start...
[  225.935970] Busfreq OPTEE set to 24000000 done! cpu=0
[  225.975879]
[  225.975879] Busfreq OPTEE set from 24000000 to 400000000 start...
[  226.012141] Busfreq OPTEE set to 400000000 done! cpu=0
[  229.127121]
[  229.127121] Busfreq OPTEE set from 400000000 to 24000000 start...
[  229.135966] Busfreq OPTEE set to 24000000 done! cpu=0
[  229.176856]
[  229.176856] Busfreq OPTEE set from 24000000 to 400000000 start...
[  229.212407] Busfreq OPTEE set to 400000000 done! cpu=0
[  232.487115]
[  232.487115] Busfreq OPTEE set from 400000000 to 24000000 start...
[  232.495906] Busfreq OPTEE set to 24000000 done! cpu=0
[  232.536256]
[  232.536256] Busfreq OPTEE set from 24000000 to 400000000 start...
[  232.571992] Busfreq OPTEE set to 400000000 done! cpu=0
[  235.687101]
[  235.687101] Busfreq OPTEE set from 400000000 to 24000000 start...
[  235.695880] Busfreq OPTEE set to 24000000 done! cpu=0
[  235.754748]
[  235.754748] Busfreq OPTEE set from 24000000 to 400000000 start...
[  235.781876] Busfreq OPTEE set to 400000000 done! cpu=0

[igorpadykov]

Hi layleon

what processor and bsp used in the case. Is it possible to reproduce issue on some nxp

reference board with demo images from:

https://www.nxp.com/design/software/embedded-software/i-mx-software/embedded-linux-for-i-mx-applicat...

Best regards
igor

[layleon]

BSP:5.4.47_2.2.0​​

Self-designed hardware, using IMX6UL.

Boot from NAND.

[igorpadykov]

"Self-designed hardware" - uses pmic or based on nxp i.MX6UL EVK reference design ?

Best regards
igor

[layleon]

fixed 3V3/1V2/1V35 by DC-DC converter

The same DDR P/N, 128MB NAND, has been booted and the DDR has been calibrated.

Reading the code, it looks like the DDR frequency keeps changing(periodicity) from 24MHz to 400MHz(400MHz to 24MHz), which triggers this change, why is this? This output is very disturbing to debug ah.

[igorpadykov · Accepted solution]

one can look at sect.2.5.4 Dynamic Bus Frequency  i.MX Linux Reference Manual​

so if voltages are fixed, busfreq driver may be disabled. Depending on processor load voltages may

vary as "fsl,soc-operating-points" show in dts

https://source.codeaurora.org/external/imx/linux-imx/tree/arch/arm/boot/dts/imx6ull.dtsi?h=imx_5.4.4...

Best regards
igor

[layleon]

Example Patch,both the kernel(linux-imx) and the bootloder(u-boot) need to be patched.

diff --git a/arch/arm/boot/dts/imx6ul.dtsi b/arch/arm/boot/dts/imx6ul.dtsi
index 3a9985cb0dd9..e0809eabf4ff 100644
--- a/arch/arm/boot/dts/imx6ul.dtsi
+++ b/arch/arm/boot/dts/imx6ul.dtsi
@@ -59,22 +59,16 @@
 			compatible = "arm,cortex-a7";
 			device_type = "cpu";
 			reg = <0>;
-			clock-frequency = <696000000>;
+			clock-frequency = <528000000>;
 			clock-latency = <61036>; /* two CLK32 periods */
 			#cooling-cells = <2>;
 			operating-points = <
 				/* kHz	uV */
-				696000	1275000
 				528000	1175000
-				396000	1025000
-				198000	950000
 			>;
 			fsl,soc-operating-points = <
 				/* KHz	uV */
-				696000	1275000
 				528000	1175000
-				396000	1175000
-				198000	1175000
 			>;
 			clocks = <&clks IMX6UL_CLK_ARM>,
 				 <&clks IMX6UL_CLK_PLL2_BUS>,