topic Re: questions about MMDC Linux driver in BSP in i.MX Processors

questions about MMDC Linux driver in BSP

ko-hey — Wed, 07 Feb 2018 01:00:48 GMT

Hi all

I have issue and questions about MMDC Linux driver in BSP L4.9.11.
It is a problem that a running CPU stops suddenly.
Of course it is possible to recover with the WDT, but I want to find out the cause.

Break down the issue into parts, I found that the issue is DDR and CPU communication.
Then I tested with DDR Stress Test V2.8 and it passed.
On the other hand, the Read/Write test with Linux failed.

As a result, I guess something is wrong with the Linux driver.
Could you teach me following questions ?

Q1.
In my understanding, all of the process and sequence in the drivers are based on the completion flag.
Am I correct ?

Q2.
I konw that the characteristics of the LSI changes with temperature.
Is the driver of the evaluation board made assuming about low and high temperature condition as well ?

Q3.
Is there a possibility of deviating from the timing spec described in the data sheet at low and high temperature ?

Ko-hey

Re: questions about MMDC Linux driver in BSP

Yuri — Wed, 07 Feb 2018 03:18:11 GMT

Hello,

Please verify memory initialization parameters for Linux - if they

are the same as for the DDR Stress test. Difference between initialization

parameters may cause the problem with memory in Linux. Let me remind,

initialization parameters for the Stress test are located in \script directory.

For Linux - in the DCD table of U-boot. Look at Chapter 3 (Porting U-Boot )

of “i.MX_BSP_Porting_Guide.pdf”.

https://www.nxp.com/webapp/Download?colCode=L4.9.11_1.0.0_LINUX_DOCS

Note, there is no special MMDC Linux driver in BSP. System memory should be just

initialized (in U-boot). Nothing more.

Have a great day,
Yuri

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Re: questions about MMDC Linux driver in BSP

ko-hey — Wed, 07 Feb 2018 07:11:01 GMT

Hi Yuri Muhin

Do the initialization parameters which you mentioned mean MMDC register settings ?

Ko-hey

Re: questions about MMDC Linux driver in BSP

Yuri — Wed, 07 Feb 2018 08:53:11 GMT

Hello,

Correct, I mean mainly MMDC register settings.

Regards,

Yuri.

Re: questions about MMDC Linux driver in BSP

ko-hey — Thu, 08 Feb 2018 00:46:41 GMT

Hi Yuri Muhin

Okay, I'll check it.

How about my above questions ?

Are there correct ?

Ko-hey

Re: questions about MMDC Linux driver in BSP

Yuri — Fri, 09 Feb 2018 09:21:42 GMT

Hello,

All boards, temperature, environment conditions should be taken into considerations

when calibrating, testing memory, say with the DDR Stress - so that average values

for memory parameters be used during memory initialization; assuming ZQ may be

implemented automatically in real time. Linux in itself does not perform activities for it.

Regards,

Yuri.