[U-Boot-Custodians] SPL / TPL

Joe Hershberger joe.hershberger at gmail.com
Wed Oct 9 20:04:52 UTC 2019

Hi Wolfgang,

On Wed, Oct 9, 2019 at 12:44 PM Wolfgang Denk <wd at denx.de> wrote:
> Dear Bin Meng,
> In message <CAEUhbmU0wox4nk+Mmee9YAPEroipT=635PVMrGVCH6Hw-JW4PQ at mail.gmail.com> you wrote:
> >
> > I also thought TPL is 3rd program loader, but some platforms (as
> > pointed out in this email thread) use TPL as the 1st stage program
> > loader proceeding SPL, and in fact changed its meaning to Tiny Program
> > Loader.
> They may think so, but they are wrong.  Inventing a new name to
> mascerade their error does not make things better.
> > Indeed people are not in agreement. That's why I sent this email
> > asking for some clarification :)
> Yes, much appriated.
> > Apparently there are 2 distinct implementation about TPL in U-Boot
> > today. So what should we do next?
> Those systems which have the implementation swapped should fix their
> boards / platforms such that the code started by the ROM boot loader
> is built as SPL, and that the code which runs after the SPL is built
> as TPL.
> Nobody in a sane state of mind counts 1 - 3 - 2 ;-)

I agree that this term should not be hijacked. I think that what is
likely is that they needed a new thing even smaller than SPL and
didn't need a thing bigger than SPL that wasn't already just U-Boot,
and just hijaked the configuration that existed since it (TPL) is far
less mature and used in far fewer scenarios. I think they should have
made a different config and different name for their case... Early
Program Loader? I don't know.

The one thing that I'm glad they didn't do is re-implement all of SPL
as TPL just because they need an additional binary. I suspect there is
a fair amount of refactoring needed if that is the goal you are hoping


> Best regards,
> Wolfgang Denk
> --
> DENX Software Engineering GmbH,      Managing Director: Wolfgang Denk
> HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
> Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
> "The first rule of magic is simple. Don't waste your time waving your
> hands and hoping when a rock or a club will do."
>                                                - McCloctnik the Lucid
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