[U-Boot-Users] U-Boot-NG ?

Wolfgang Denk
2007-07-03T22:55:00Z

Dear Sascha,

in message <20070703223156.GD8839@pengutronix.de> you wrote:
>
> > Yes, but "provide a little bit of debug output" means printf() and
> > friends, plus console drivers, which in turn means reading the
> > environment (for the console baudrate) and probably the device tree
> > (for the hardware configuration of the console port), etc.
>
> I think you're talking about two different things here. The debug output

No, actually I'm not.

> you want to see has nothing to do with the output in normal use. When
> bringing up a green board I would not ask the environment for the
> baudrate, because there is none.

You are right as far as dedicated debug output is concerned, which is
normally not active or even present in the code of a release version.
But please see my other messages: I still want to be able to *see*
what's going on in my system and where it eventually might get stuck,
including in the release versions of the code.

> Thinking about this U-Boot already has this. Only the way it is done
> became very messy over the years. Not only this mailing list but also
> the code looks like a struggling between the people who want early
> debug output and the people who want to configure their console in the
> environment, possibly disabling it completely. People with multiple
> serial ports not to mention...

Please be aware that work is going on to make hardware features
(including the console port) configurable at runtime by interpreting
information passed in a device tree image. This is a requirement that
makes things even more complicated here. And one that cannot be
dropped easily as it solves a real problem for a couple of users.

> The console thing is symptomatic for other cases in U-Boot aswell. This
> is why I think we need to start with a cleaner codebase where a driver
> or board support only enters after it works with a to be defined API.

Well, then we have to make sure that console driver can be entered
very, very early. Ideally, it is the first thing U-Boot should do.

> > Assume something like a MPC8xx with console on SMC1 or SMC2, depending
> > on that the device tree says...
>
> Sounds like calling the president for turning on the lights. Please do

I'm not sure what you mean here.

> not forget that there are also other people. None of our customers ever
> asked for a even configurable console. 115200 port0 seems to fit everyone.
> Instead we have to deal with Booting from small boot sectors.

I never said that U-Boot was a trivial thing, and I am very well aware
that we have a wide range of requirements, which sometimes may even be
conflicting.

We are discussing these things here so that you understand our
requirements, as we understand yours. Then lets together find a
solution which works for everybody.

Best regards,

Wolfgang Denk

--
DENX Software Engineering GmbH, MD: Wolfgang Denk & Detlev Zundel
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
There is is no reason for any individual to have a computer in their
home. -- Ken Olsen (President of Digital Equipment Corporation),
Convention of the World Future Society, in Boston, 1977