imx7

[kayiyeh]

Hi there,

I got an imx7ulpevk board. For some reason, the DRAM was changed to a 2Gb LPDDR4. After that, it passes the stress test using the ddr_stress_tester_v3.00 and can run up to 500MHz. However, I didn't find "genuine" document regarding how to build a linux kernel for imx7 that can accommodate the change of the DRAM. When I use the default kernel image download from NXP web site, there is nothing coming out from debug port so I can't not check anything wrong. 

Please help and thanks in advance.

BR,

KY

[igorpadykov]

Hi Ka-Yi

one can look at Porting Guide in Linux L4.14.78_1.0.0 Documentation

General steps are to update dcd header (imximage.cfg) with new ddr calibration settings

found from ddr tester

mx7ulp_evk\freescale\board - uboot-imx - i.MX U-Boot 

Memory size can be adjusted with #define PHYS_SDRAM_SIZE   in

uboot/include/configs/mx7ulp_evk.h   

mx7ulp_evk.h\configs\include - uboot-imx - i.MX U-Boot 

Best regards
igor
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[kayiyeh]

Dear Igor,

Thank you for your quick response. I tried the suggestion you gave me, and download the u-boot source. However, I don’t know how to change the DCD or the imximage.cfg file. The reason is that all I got from the ddr stress tool is a calibration log, which I attached in this file. I see nothing similar between the file and the imximage.cfg. Could you give me more hint? Do I get the wrong ddr stress tool?

Regards,

Ka-Yi Yeh

[igorpadykov]

Hi Ka-Yi

changes are performed manually, may be useful to check ddr tool presentation

DES-N1936 i.MX 6UltraLite DDR Tools Overview and Hardware Design Considerations 

Best regards
igor

[kayiyeh]

Dear Igor,

Thanks a lot. I will study more. However, I have more questions. You suggest some files need to be changed in the previous mail. Because I found using Yocto project to build SD card is more straightforward for me, I want to build kernel/uboot from Yocto. But I found there are same file names. I don’t know which one is correct one? For example, under my build directory, there are 107 imximage.cfg files. I can rule out many of them because the directory name suggest they are not relevant, but there are still many files I can’t tell. BTW, I use “fsl-imx-fb” distro because all I need is command line interface.

Regards,

Ka-Yi Yeh