[U-Boot] ns16550: tegra: Specify debugging serial port at boot.

[Wolfgang Denk]

Dear Stephen Warren,

In message <4F58F5B8.6070402 at wwwdotorg.org> you wrote:
>
> I noticed this patch isn't applied yet that I can find. Are there any
> comments on it; can it be applied? Thanks.
> 
> For reference, it's in patchwork at:
> http://patchwork.ozlabs.org/patch/134712/
> 
> > ---
> > drivers/serial/ns16550.c |    7 +++++++
> >  1 files changed, 7 insertions(+), 0 deletions(-)
> > 
> > diff --git a/drivers/serial/ns16550.c b/drivers/serial/ns16550.c
> > index 0c23955..19a28cd 100644
> > --- a/drivers/serial/ns16550.c
> > +++ b/drivers/serial/ns16550.c
> > @@ -62,6 +62,13 @@ void NS16550_init(NS16550_t com_port, int baud_divisor)
> >  	serial_out(0, &com_port->mdr1);
> >  #endif
> >  #endif /* CONFIG_OMAP */
> > +#if defined(CONFIG_TEGRA2)
> > +	/*
> > +	 * Put a 'D' in the scratchpad to let the kernel know which UART
> > +	 * for earlyprintk [D]ebugging.
> > +	 */
> > +	serial_out('D', &com_port->spr);
> > +#endif
> >  }

I don't like to see such highly architecture specific stuff in common
code, especially if it's such a dirty hack like this.

I don't really understand the arguments for the need of this patch
either.  There are standard ways for passing hardware consifuration to
the kernel, and the comment shows that you are aware of these.

Inventing yet another hackish method seems not a good idea to me.

Best regards,

Wolfgang Denk

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