[U-Boot] [PATCH v2 22/22] omap: spl: add more debug traces

Wolfgang Denk
2011-06-15T10:18:29Z

Dear Aneesh V,

In message <4DF617C2.6070100@ti.com> you wrote:
>
> > Console should _always_ be enabled as early as possible,
>
> Unfortunately this is not the case with U-Boot today. Console
> initialization happens in board_init_f(). Before board_init_f()
> typically a lot of(in fact most of) low level initialization happens
> through the lowlevel_init() function called from start.S and the
> initial part of init_sequence()

As the name LOWLEVEL_init() suggests, this is suppoed to contain
always only the bare minimum of initialization that is necessary to
get the CPU running. All more complex initializations should be
delayed and only be run when we have a proper environment, including
debug output on the console.

> > Can we not rather change the code so both configurations behave the
> > same?
>
> In SPL I had more flexibility, so I do a simplified init of console
> right at the beginning of lowlevel_init(), so I can use debug prints in
> lowlevel_init(). Some part of our lowlevel_init() that is executed in
> SPL path may also be executed by U-Boot if it runs from NOR flash, but
> in this case console wouldn't be ready. That's why I made the macro.

I do not understand this. How can you have more flexibility in the
more restricted environment?

We definitely should unify this.

> No. That wouldn't serve the purpose. I need two macros to distinguish
> between the two cases.
> 1. 'debug()' - can be used in all places at which console is guaranteed
> to be initialized whether executed as part of U-Boot or SPL.
> 2. 'spl_debug()' to be used at places where console is initialized for
> SPL but not for U-Boot (eg. lowlevel_init()) - so emit no code for
> U-Boot.

You see - this distinction is becoming a mess. Let's get rid of this
and use common code for both cases.

Best regards,

Wolfgang Denk

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