topic Re: How to running the i.mx6q from 792MHz to 996MHz on the Linux 3.14.28? in i.MX Processors

How to running the i.mx6q from 792MHz to 996MHz on the Linux 3.14.28?

michael_lee — Wed, 20 Jul 2016 09:45:44 GMT

Dear NXP and All,

I am debugging the i.mx6q chip on the Linux 3.14.28, sabresd demo board, I use the default software, Its freq is 792MHz, my chip support 1GHz, so I want to run the 996MHz, Can anyone give me the steps about the freq change? Thanks.

I have read the "i.MX_6_Linux_Reference_Manual.pdf", Chapter 24 CPU Frequency Scaling (CPUFREQ) Driver,

but It doesn't say how to change freq?

Best Regards,

Re: How to running the i.mx6q from 792MHz to 996MHz on the Linux 3.14.28?

igorpadykov — Wed, 20 Jul 2016 11:30:24 GMT

Hi Michael

default bsp supports it, pelase refer to operating-points in imx6q.dtsi

linux-2.6-imx.git - Freescale i.MX Linux Tree

for procedure of changing frequency refer to Chapter 24

CPU Frequency Scaling (CPUFREQ) Driver attached Linux Manual.

Best regards

igor

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Re: How to running the i.mx6q from 792MHz to 996MHz on the Linux 3.14.28?

michael_lee — Wed, 20 Jul 2016 12:01:47 GMT

Dear igor,

default BSP suport DVFS, but usually it works on 792MHz, so I want to work on 996MHz,

and which doc you suggested that it doesn't show how to change the freq?

do you have the doc about this issue step by step to guide us to configure it ?

or can you show me an example, we can download it to verify, thanks.

Best Regards,

Re: How to running the i.mx6q from 792MHz to 996MHz on the Linux 3.14.28?

igorpadykov — Wed, 20 Jul 2016 13:46:05 GMT

Hi Michael

it does show how to change the freq, for example:

echo 792000 > /sys/devices/system/cpu/cpu0/cpufreq/scaling_setspeed

To view what values the CPU frequency can be changed to in KHz (The values in the

first column are the frequency values) use this command:

cat /sys/devices/system/cpu/cpu0/cpufreq/stats/time_in_state

what is full processor part number in the case ?

Best regards

igor

Re: How to running the i.mx6q from 792MHz to 996MHz on the Linux 3.14.28?

michael_lee — Wed, 20 Jul 2016 13:55:23 GMT

Dear igor,

Do you check the command which you suggest?

On the Linux 3.14.28, it can't run!

root@imx6qsabresd:/sys/devices/system/cpu/cpu0# ls -l

drwxr-xr-x 4 root root 0 Jun 3 00:29 cpuidle

-rw-r--r-- 1 root root 4096 Jun 3 00:29 online

drwxr-xr-x 2 root root 0 Jun 3 00:29 power

lrwxrwxrwx 1 root root 0 Jan 1 1970 subsystem -> ../../../../bus/cpu

drwxr-xr-x 2 root root 0 Jun 3 00:29 topology

-rw-r--r-- 1 root root 4096 Jan 1 1970 uevent

there is not the file "cpufreq/stats/time_in_state“

Have you check that?

which part number I use is MCIMX6Q5EYM10AD.

Best Regards,

Re: How to running the i.mx6q from 792MHz to 996MHz on the Linux 3.14.28?

igorpadykov — Thu, 21 Jul 2016 00:41:59 GMT

Hi Michael

what image is used in the case, could you try Demo image on

L3.14.28_1.0.0_iMX6QDLS_BUNDLE

http://www.nxp.com/webapp/Download?colCode=L3.14.28_1.0.0_iMX6QDLS_BUNDLE&Parent_nodeId=1337699481071706174845&Parent_pageType=product&Parent_nodeId=1337699481071706174845&Parent_pageType=product

also please check (with jtag or in uboot ) fuse SPEED_GRADING[5:4] address 0x440[17:16]

Table 5-10. Fusemap Descriptions i.MX6DQ Reference Manual (rev.0 2/2016)

http://cache.nxp.com/files/soft_dev_tools/doc/support_info/iMX6DQPRM.pdf

Best regards

igor

Re: How to running the i.mx6q from 792MHz to 996MHz on the Linux 3.14.28?

michael_lee — Thu, 21 Jul 2016 01:37:58 GMT

Dear igor,

I use the mfgtools which support the L3.14.28 version, and use the default image;

do you know the command like this "echo 792000 > /sys/devices/system/cpu/cpu0/cpufreq/scaling_setspeed" can be used for the L3.0.35 version,

Best regards,

Re: How to running the i.mx6q from 792MHz to 996MHz on the Linux 3.14.28?

BiyongSUN — Thu, 21 Jul 2016 06:41:39 GMT

Michael,

It is a Linux topic, please read the Linux documents

Documentation/cpu-freq/user-guide.txt

Documentation/cpu-freq/governors.txt

This is in governors.txt

scaling_available_governors : this file shows the CPUfreq governors available in this kernel. You can see the

currently activated governor in

scaling_governor, and by "echoing" the name of another governor you can change it. Please note

that some governors won't load - they only

work on some specific architectures or

processor

Please check if the current governor is "userspace". Normally the gavernors could be "userspace performance interactive ondemand conservative powersave".

If not, please change it to "userspace".