AM3356: How to force operating mode OPP100under u-boot/linux

O.H

Part Number: AM3356

Hi experts,

Could you tell me how to fix it to run at 600MHz (OPP100) at boot time (u-boot)? It would be helpful if you could tell me exactly which file to fix and how to do it.

My client is using AM3356BZCZA60 and would like to see if AM335xBZCZA80 or AM335xBZCZA100 could be used as an alternative. We would like to make sure that the operating frequency does not change on them.
Specifically, we want to make sure that no matter which model number we bring, it will operate at 600MHz.

Best regards,
O.H

over 2 years ago

0 Bin Liu over 2 years ago

TI__Guru**** 168181 points

Hi,

I am routing your query to our U-Boot expert for comments.

0 Hong Guan64 over 2 years ago in reply to Bin Liu

TI__Guru 68420 points

Hello O.H
Yes, it is doable.
Please refer to the e2e posts, especially the first one.
e2e.ti.com/.../1004863
e2e.ti.com/.../983974
Best,
-Hong

0 O.H over 2 years ago in reply to Hong Guan64

Mastermind 6330 points

Hello Hong,

We ware able to change the operating frequency based on the information you provided.

However, I believe that something is missing from the process because there is a difference in current consumption.

Is there any special processing or setting required to use AM3358BZCZA80 in the same environment as AM3356BZCZA60?
Besides the operating frequency, are there any other parameters that change, or are there any differences in settings depending on the model number?

Best regards,
O.H

0 Hong Guan64 over 2 years ago in reply to O.H

TI__Guru 68420 points

Hello O.H
Have you checked the available cpufreq and regulator summary once Linux kernel up running with DVFS on your board?
root@am335x-evm:~# cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequencies
root@am335x-evm:~# cat /sys/kernel/debug/regulator/regulator_summary

The sample log is in the previous referenced e2e
e2e.ti.com/.../1004863
- am3_6.3_regulator_600MHz.txt: the log captured on AM335x GP EVM (1GHZ P/N) using the code changes to ceiling max speed to 600MHz.

Best,
-Hong

0 Hong Guan64 over 2 years ago in reply to Hong Guan64

TI__Guru 68420 points

I noticed AM3358x is mentioned in your last reply.
AM3358x has SGX graphic IP, and you may want to check this e2e for power saving in case SGX is not needed for your user case
e2e.ti.com/.../2854172
Best,
-Hong

0 O.H over 2 years ago in reply to Hong Guan64

Mastermind 6330 points

Hello Hong,

I missed the part about the SGX difference...
We will pass your response on to the customer and let you know when we know the outcome.

Best regards,
O.H

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AM3356: How to force operating mode OPP100under u-boot/linux