[U-Boot] [PATCH V5 00/31] imx: add i.MX8M support and i.MX8MQ EVK

[Peng Fan]

Hi Jon,

> -----Original Message-----
> From: Jon Nettleton [mailto:jon at solid-run.com]
> Sent: 2018年9月7日 14:03
> To: Fabio Estevam <festevam at gmail.com>
> Cc: Peng Fan <peng.fan at nxp.com>; Diego Dorta <diegohdorta at gmail.com>;
> Fabio Estevam <fabio.estevam at nxp.com>; U-Boot Mailing List
> <u-boot at lists.denx.de>
> Subject: Re: [U-Boot] [PATCH V5 00/31] imx: add i.MX8M support and i.MX8MQ
> EVK
> 
> On Thu, Sep 6, 2018 at 3:37 PM Fabio Estevam <festevam at gmail.com> wrote:
> >
> > Hi Peng,
> >
> > On Fri, Aug 31, 2018 at 3:27 AM, Jon Nettleton <jon at solid-run.com> wrote:
> >
> > > Peng,
> > >
> > > Will you be releasing the script you are using to convert that code
> > > generated by the ddr training tool into this format?  I would like
> > > to test your patchset on our new SOMs and that would be very useful.
> >
> > Any comments about the DDR init script? Looks like we are stuck in
> > this issue for a long time.
> >
> 
> I have been chewing on this over the past week, and I am starting to think that
> u-boot is not necessarily the right place for the DDR initialization for this
> platform.  We require ATF in order to load the
> lpddr4 firmware regardless, so why not do the DDR training and configuration
> there?  This would also abstract out the proprietary memory bits so the code
> doesn't need to be re-duplicated in the various bootloaders.  In theory it should
> also simplify the MX8 image scripts since SPL would not be a requirement.

On i.MX8M, SPL is used to initialize DDR and load ATF/TEE/U-Boot to memory and kick ATF.

Two option:
1. Move DDR code out of SPL and make it a standalone image, then pad it the SPL. The drawback is
 need a new repo holding ddr code.
2. Restructure the DDR code the make it generic enough.
  One engineer in NXP is looking into restructure code, but priority is low.

Regards,
Peng.

> 
> Thoughts?