Re: [Etherboot-developers] Etherboot questions

[Paul <pau...@vi...>]

On Tue, 2003-03-18 at 13:38, Eric W. Biederman wrote:
> Paul <pau...@vi...> writes:
> 
> > I am currently considering using an open source bootloader (ROLO) on an
> > embedded PC.  However, ROLO currently does not support ethernet
> > booting.  I am considering adding this functionality.  I am trying to
> > get a grip on what I need to do so that I can estimate how much effort I
> > would need to put in.  I have two questions:
> > 
> > (1) What are the BIOS requirements of Etherboot? (ROLO doesn't have too
> > much in the way of BIOS services so any required will probably have to
> > be added).
> 
> Etherboot depends on no BIOS services.
> 
> With that said it does need a clock that counts up, and it assumes
> the pci or other pnp devices have already had their resources
> assigned.

OK - I'll have a look at where etherboot uses the clock - My embedded PC
has an AMD Elan 520 processor on it which has standard PC stuff
integrated along with it.  

I have only just started looking at ROLO and Etherboot source code so
I'm not exactly sure what I need to do yet.  I didn't see pci bus
enumeration/resource allocation going on in ROLO so I am assuming that
this is left to Linux.  However, clearly the PCI registers in the
ethernet device will need to be enabled - and perhaps the interrupt? -
again I haven't yet concluded whether Etherboot uses an interrupt... 

> A current user of etherboot is LinuxBIOS which provides no BIOS
> services.
> 
> > (2) I have a PCI ethernet device (Intel GD82559ER) and I would like to
> > incorporate Etherboot into the boards main boot PROM (there is no socket
> > specifically for the ethernet device).  I couldn't find any information
> > in the documentation that describes doing this.  What steps would I need
> > to take to accomplish this?
> 
> Etherboot can build as a standard option rom, and if the boards BIOS
> supports incorporating such you are done.  Or else you can be more
> creative.
> 
> And etherboot has been ported to the Itanium so it has the worst
> of the portability problems worked out.
> 
> Eric
> 

If an etherboot build can provide me with a BIOS extension ROM image for
my PCI ethernet controller device then I can put it straight into my
boot PROM at the appropriate address.  ROLO doesn't appear to do any
searching for BIOS extensions but this shouldn't be too much of a
problem to add some code so that it finds the image provided by
etherboot.

Thanks,

PT.