Re: [PATCH 04/23] ARM: i.MX8M: add support to pass DT via imx8m{m,n,q,p}_load_and_start_image_via_tfa()

[Marco Felsch <m.felsch@pengutronix.de>]

Hi Ahmad,

On 26-01-15, Ahmad Fatoum wrote:
> Hi,
> 
> On 1/15/26 3:01 PM, Ahmad Fatoum wrote:
> > I have grown to dislike the boilerplate nature of our PBL entry points.
> > I want to rework this fully in the coming months, so I would prefer not
> > to add intermediate breakage till then, so users can switch at once to
> > the new model.
> 
> I think I need to clarify this a little:
> 
> It's fine to break out-of-tree code. If it's some breakage that may
> easily be missed by users, we add a migration guide entry.
> That's why we have the guides in the first place.

Good point, I missed to add an entry for it.

> In this case, I believe handover is a good solution on its own merits
> and not introducing unnecessary breakage right now is a good side-effect.

I get your point regarding the unnecessary breakage. It would have been
nice if we could have a TF-A loading abstraction within the PBL since
loading the TF-A and (opt. OP-TEE OS) is mostly the same on each and
every ARMv8-A SoC and we tend to adapt barebox rather than adapting the
TF-A binary.

However I would like to mention that handover data was meant to be
passing data between the PBL and barebox. We would repurpose the
handover mechanism if we would use the handover data. In this case it
could be re-used in several other places. Therefore I'm not a fan of
this idea.

What do you think about adding the 'fdt' support only to the 'lowlevel'
APIs:
  - __imx8mp_load_and_start_image_via_tfa()
  - __imx8mm_load_and_start_image_via_tfa()
  - __imx8mn_load_and_start_image_via_tfa()
?

These APIs are most certainly not used by anyone who is using the
current standard way of booting OP-TEE for these platforms. Of course we
could also add helpers like:

imx8mn_load_and_start_image_via_tfa_with_fdt()

but the naming is becoming very clunky.

> if it turns out to not work out of the box or complicate things in an
> disproportionate manner, please let me know and we can re-evaluate.

Please see my above points.

Regards,
  Marco

> 
> Thanks,
> Ahmad
> 
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