[U-Boot] [PATCH V2] Add Boundary Devices Nitrogen6X boards

Wolfgang Denk wd at denx.de
Sun Mar 10 16:45:11 CET 2013


Dear Eric Nelson,

In message <513CA21E.1040608 at boundarydevices.com> you wrote:
> 
> > In this case it should be possible to configure U-Boot for the maximum
> > possible RAM size (2 GB here?), then have get_ram_size() detect the
> > actual available amount, and then adjust settings as needed.
> 
> I'm not certain.
> 
> The JEDEC spec for the DDR devices we're using have quite different
> settings in a couple of areas. In particular, the tRFC value is
> quite different between densities.

Well, of course.  Different memory types / sizes will require
different initialization.  But this you already have in place.  Now go
the final step and auto-select the configuration instead of having the
user (and manufacturer, and service, etc.) all suffer from the pain of
always needing to know which exact configuration is needed on some
board.

> That throws a wrinkle into the whole patch set, since all of
> this code presumes that we're running from DDR and other
> calibration data was also gathered based on the actual parts
> used.

This is wrong then and needs to be fixed.  get_ram_size() should be
used before relocation into RAM.


Best regards,

Wolfgang Denk

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Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
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