Calibrating different LPDDR2 chips on the fly

[lazarivanovic]

Hi all, I'm using iMX6DL processor and I have two possible LPDDR2 chips that can be used in the device production.

I am wondering is there some way to write, at boot loader (u-Boot) runtime, different values in MMDC registers, depending on memory chip used?

For example is there some way to:

1. detect memory chip
2. use DCD set that writes to MMDC registers appropriate values for detected memory chip (or set this after boot loader is initialized)

I know that DCD is static image that is read by processor from exact location, and that this solution probably is not possible, but just want to ask if someone have an idea how this problem can be solved.

Thanks a lot,

Lazar

[art]

Yes, you are right in that it is not possible to detect LPDDR2 chip model and appropriately configure MMDC by uboot since in that case there is a contradiction: uboot cannot be started until the memory is initialized, but the memory cannot be initialized until uboot detects the memory type...

Another way of implementing your task is to write a small piece of code that is loaded into the processor's internal SRAM, then it detects and appropriately initializes LPDDR2 and then loads the rest of the code (e.g. uboot) there.

Unfortunately, we don't have a ready-to-use solution for that.

Have a great day,
Artur

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[lazarivanovic]

Thanks for the advice Artur. I will try to solve this by making some kind of uBoot pre-loader. I just wondered if this can be accomplished within uBoot before its relocation to RAM.

Do you by any chance have some example code (that you can share), from which I can start making this uBoot pre-loader?

Thanks,

Lazar

[Yuri]

Hello,

please look at the example, attached in the following thread :

Integrating Processor Expert for i.MX and ARM GCC with Eclipse

Regards,

Yuri.

[gusarambula]

Thank you, Artur.
Forgot to chose pick. Reassigned.