iMX8MP config with 4GB LPDDR

[Charled]

Hi,

We are working on a board based on iMX8MP chipset, derivated from the evaluation board EVK-IMX8MP, where we have only 4GB instead of 6GB for the DDR. We are using Android 11.0.0_1.2, and we don't use yet Trusty (but it will be activated later).

I haven't find any document explaining the DDR memory footprint. Did you have such? I would be interested.
Now, I have tried different things, but I cannot find a valid configuration allowing to boot Android with my 4GB DDR. In the uboot git repository, I have tried to modify the files:

• include/configs/imx8mp_evk.h
  • PHYS_SDRAM_SIZE = 3GB, PHYS_SDRAM_2_SIZE = 1GB
  • PHYS_SDRAM_SIZE = 2GB, PHYS_SDRAM_2_SIZE = 2GB
• arch/arm/dts//imx8mp-evk.h
  • Change the memory@40000000 node, trying to align also to 4 GB, with 3 + 1 or 2+2

But I cannot start Android correctly. Depending on the configuration, I can be blocked in the early stages of the kernel startup, or a crash later, during the Android initialization. Stangely, if I dclare only 2GB (in both files above), it starts correctly....

Do you have any guidelines or documents explaining how to define the memory footprint, and fix my issue to reduce from 6GB to 4GB?

Thanks

Charles-Edouard

[Charled]

Thank you for your answer. I finally found my issue, running again the DDR tool and get the lastest configuration.

Best Regards

[AldoG]

Hello,

The changes you have made look correct, you'll have to make changes accordingly to the dts for android as well for CMA reserved memory.

Also, I would like to know if you had run and pass the ddr stress test for the memory you're using
https://community.nxp.com/t5/i-MX-Processors-Knowledge-Base/i-MX-8M-Family-DDR-Tool-Release/ta-p/110...

Best regards,
Aldo.