[U-Boot-Custodians] SPL / TPL

Tom Rini trini at konsulko.com
Mon Oct 14 21:52:48 UTC 2019

On Mon, Oct 14, 2019 at 10:18:42AM +0200, Wolfgang Denk wrote:
> Dear Tom,
> In message <20191010190807.GB6716 at bill-the-cat> you wrote:
> > 
> > This last point here is what I'm also wondering about.  My gut is that
> > README.TPL is more "old aspiration" than "what we have implemented".
> It is not "aspiration", but documentation of how things are/were
> intended to be used.
> It is sad that we have not enough documentation, but it is even more
> sad that existing documentation gats ignored.  What I finx really
> disappointing is that we then start inventing new names to justify
> the implementation errors.
> > And, setting aside some of the back-and-forth jumps we can have, the
> > flow is:
> > ROM/etc -> Tiny Program Loader -> SPL -> U-Boot or Linux
> Sorry, this is not acceptable, and it will not work.  Explaining TPL
> as "tiny" may be applicable in some cases, but not always.  I think
> there are use cases where size(SPL) < size(TPL) so this name makes
> no sense for general use.

Note that I think the case here is also where SPL loads TPL and is the
PowerPC use-case.

> If you want to change the order from
> 	RBL -> SPL -> TPL -> U-Boot -> OS 
> [ignoring falcon mode] into something else, you should completely
> drop the names "SPL" and "TPL" which have a meaning attached (and
> more than one interpretation), and use completely new names which
> do not depend on properties as size.
> As a lesson learned from history you should also chose names that do
> not refer to execution order, as people tend to ignore that or they
> change direction while counting from 1 to 3 :-( 

In hindsight, yes, "SPL" and "TPL" are both not great names.  As we're a
few years in to this I do hesitate on any further name changing.

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