[Rock Pi 4+] Mainline LPDDR4 RAM initialisation is not sufficient to boot successfully

[Lee Jones]

On Fri, 17 Jun 2022, cym at rock-chips.com wrote:

> Could you  help us to get the DRAM part number which initialization failures on the Rock Pi 4+. 

I have tested 3 boards; one appears to be fully working, on another 1
of the 2 LPDDR4 (Channel 1) chips consistently fails with a Col and
Cap Error and on the final one both chips (Channel 0 & 1) fail in the
same way as the last (Col and Cap errors).

All chips are: H9HCNNNBKUML

> We have found that some LPDDR4  abnormal operation at 50MHz.
> I think you can try that use 400MHz to detect capacity.

Wonderful.  This solves the problem.  Thank you so much!

Would you like to submit this into upstream U-boot yourself, or would
you like me to do that for you?

If the former, please Cc me on the patch and add my:

  Tested-by Lee Jones <lee.jones at linaro.org>

If the latter, please let me know and I'll do what I can to help.

-- 
Lee Jones [李琼斯]
Principal Technical Lead - Developer Services
Linaro.org │ Open source software for Arm SoCs
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