[U-Boot] [PATCH V5 31/31] imx: add i.MX8MQ EVK support

[Wolfgang Denk]

Dear Andre,

In message <552c6e47-c700-829f-c03b-a8576f616050 at arm.com> you wrote:
> 
> > Regarding the DDR firmware: I would like to start a discussion with NXP
> > and Synopsys about making the firmware free software/open source.
> 
> Don't want to temper your enthusiasm, but I believe this has been tried
> before - in vain. Hence my proposal to work around this. This is a
> common problem for many platforms: DDR training or initialisation code
> is not documented and/or provided as a closed source blob.
> I very much appreciate your push for FOSS code, but I guess this is
> where reality kicks in.

Reality can be changed. This has been done before.

Yes, some vendors think they have their crown jewels buried in their
RAM training or initialization code - of they realize it is so badly
written that they cannot allow other people to see it.

But we should always try to reduce such closed source parts to the
extend possible, and there have been a few cases where this
succeeded.  For example, it took quite some effort until Marvell
released the DDR3 init code under a License that allowed to
integrate it into U-Boot - today, all this is in mainline.

OK, with DDR4 the situation is still different.  But at least this
shows that it is always worth trying!

> There was and is quite some reverse engineering effort around this,
> though, and a lot of similarities have been found between the DDR
> controllers in different platforms, for instance between Rockchip and
> Allwinner. I believe it would be worthwhile to go over what we have in
> U-Boot and try to unify this. AFAIK many vendors use Synopsis IP, but
> don't necessarily say so. This might lead to some insight about the
> controllers used in i.MX as well.

Of course this would be _much_ easier with at least minimal help
from the IP core / chip vendors...

> Good luck with that, but don't be disappointed ...

...and keep trying!

Best regards,

Wolfgang Denk

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