Re: 3 Serial issues up for discussion (was: Re: Serial core problems on embedded PPC)

[Matt Porter]

On Mon, Jul 29, 2002 at 10:43:41AM -0700, Tom Rini wrote:
> 
> On Mon, Jul 29, 2002 at 06:17:02PM +0100, Russell King wrote:
> 
> 
> > 1. Serial port initialisation
> > -----------------------------
> >
> > Firstly, one thing to bear in mind here is that, as Alan says "be nice
> > to make sure it was much earlier".  I guess Alan's right, so we can get
> > oopsen out of the the kernel relatively easily, even when we're using
> > framebuffer consoles.
> >
> > I'm sure Alan will enlighten us with his specific reasons if required.
> >
> > There have been several suggestions around on how to fix this table:
> >
> > a. architectures provide a sub-module to 8250.c which contains the
> >    per-port details, rather than a table in serial.h.  This would
> >    ideally mean removing serial.h completely.  The relevant object
> >    would be linked into 8250.c when 8250.c is built as a module.
> 
> I think this would work best.  On PPC this would allow us to change the
> mess of include/asm-ppc/serial.h into a slightly cleaner Makefile
> (especially if we do the automagic <platforms/platform.h> or
> <asm/platform.h> bit that's been talked about in the past) magic and we
> could use that object file as well in the bootwrapper as well.

I think this would be the cleanest method as well.  Especially when we
recognize that the asm-ppc/serial.h situation will only get worse
over time.  Every embedded PPC board designer has a unique location
for his 16550 UART(s) and we just keep adding more preprocessor
cruft for each port.  This should let us keep this board-specific
info in our board port files...more abstraction=good.

Regards,
-- 
Matt Porter
[e-mail]
This is Linux Country. On a quiet night, you can hear Windows reboot.