[U-Boot-Custodians] SPL / TPL

[Simon Glass]

Hi Wolfgang,

On Mon, 14 Oct 2019 at 01:49, Wolfgang Denk <wd at denx.de> wrote:
>
> Dear Simon,
>
> In message <CAPnjgZ1anH_NvK+WEGFfQGuQmnyGgU1GjJkHgRR91eJ7m-BTeg at mail.gmail.com> you wrote:
> >
> > Yes that's right. TPL is the first stage (as implemented) and is much
> > smaller than SPL.
>
> Size does not matter in terms of sequence, or does it?
>
> > It also makes at least some sense:
> >
> > - Secondary PL loads primary (U-Boot)
> > - Tertiary PL loads secondary (SPL)
>
> Oh, and *this* makes sense to you?

Yes it makes sense to me, but the ordering is backwards from what you
have, So it is:

Primary - U-Boot
Secondary - SPL
Tertiary - TPL
...

If we had:

first: TPL
second: SPL
third: U-Boot

then that might make some sense, but the problem is that many
platforms don't have TPL, so there is no 'first'.

It seems better to me therefore to have:

Primary - U-Boot
Secondary - SPL
Tertiary - TPL

and then platforms can choose as many levels as they need to make boot
work. God forbid if we needed quaternary we could add it and
everything would stay consistent.

Regards,
Simon