Change the DDRC_DRAMTMG registers

[ko-hey]

Hi all

We are changing RAM access frequency from 533 MHz to 133 MHz.
In that case, I also want to change DDRC_DRAMTMG together.

We want to increase access efficiency by setting WL and RL to optimal values.

I am trying to refer to the Linux lpddr3_freq_imx.s code, but there was no description about DDRC_DRAMTMG.
I checked the datasheet, but I could not find a procedure to change dynamically.

Please tell me how to change it.

Ko-hey

[Yuri]

Hello,

  the i.MX7 RM contains register's description, also customers can use the tools:

https://community.nxp.com/docs/DOC-152468 

Have a great day,

Yuri

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[ko-hey]

Hi Yuri Muhin

Sorry for lack of explanation.

I know we can set it by the tool.

After user got the value by the tool, we set it to lpddr3_freq_imx.s.

Am I correct ?

We can't find the DDRC_DRAMTMG parameters in lpddr3_freq_imx.s.

Which files do we use ?

Ko-hey

[Yuri]

Hello,

No need to change all memory parameters (in order to get most suitable values, say - just for

selected frequency). Many parameters may be set for maximal frequency and left unchanged for

other working points.

Regards,

Yuri.

[ko-hey]

Hi Yuri Muhin

Once we set all memory parameters for selected frequency, we don't need to change the parameters when we change the bus frequency.

Am I correct ?

I found the section Dynamic Bus Frequency Driver in i.MX_Linux_Reference_Manual.pdf.

From the document, it seems that it can change the freq to 24MHz and 100MHz.

Parameters have not been changed in this driver.

Am I correct ?

In other word, user need to reset for changing the DDR parameters when they want to change freq.

Am I correct ?

Ko-hey

[Yuri]

Hello,

 Most timing memory parameters, configured for highest work frequency may be left 

unchanged for lower work frequencies. Please use the recent NXP BSP codes.

Regards,

Yuri.

[ko-hey]

Hi YuriMuhin_ng‌

Sorry for late reply.

As the background of question, we want to increase access efficiency by setting WL and RL to optimal values.

I think I can improve the access efficiency by setting the WL and RL to optimal value for required freq.

Am I correct ?

If my above question is correct, could you tell me how to change and do you have sample code ?

Furthermore, I found the section Dynamic Bus Frequency Driver in i.MX_Linux_Reference_Manual.pdf.

From the document, it seems that it can change the freq to 24MHz and 100MHz.

Parameters have not been changed in this driver.

Am I correct ?

Ko-hey

[Yuri]

Hello,

   I think setting WL and RL for max frequency is quite optimal for less frequencies too.
You may rely on our BSP regarding Dynamic Bus Frequency, assuming the recent BSPs.

Regards,

Yuri.

[ko-hey]

Hi Yuri Muhin

Thank you for reply.

I'll talk to customer.

Ko-hey

[ko-hey]

Hi Yuri Muhin

Is it hard to answer soon ?

Ko-hey