progress on the adi pronghorn metro board

[John Hay]

On Thu, Mar 22, 2007 at 04:27:08PM +0100, Olivier Houchard wrote:
> On Thu, Mar 22, 2007 at 08:04:21AM -0700, Sam Leffler wrote:
> > John Hay wrote:
> > > Hi Guys,
> > > 
> > > With this patch I am at the stage where both an Avila 2348-4 and the
> > > ADI Pronghorn Metro boot from the same kernel binary. The "main" stuff
> > > is working, ie. console, ethernet and mini-pci slots. The iic bus on
> > > the Avila is still working. The one for the Pronghorn is configured,
> > > but I must still write a driver for their max6652 temperature/voltage
> > > sensor before I will know if it is really working.
> > > 
> > > The biggest difference between the 2 boards are in the 16 GPIO pins.
> > > I think there is only 1 pin that have the same function. :-/
> > > 
> > > So what I did was to create a structure and then have 2 instances of
> > > it, one with Avila values in it and one with Pronghorn values. Then
> > > early in the boot phase, the board type gets detected and a pointer
> > > gets set to the relevant structure. All the drivers then use this
> > > pointer to get the correct values. The efect is that most of the
> > > drivers needs no checks for the different boards.
> > > 
> > > What I would like to know is, if this approach is acceptable? Should
> > > I use different files to put the stuff in?
> > > 
> > > My code is not finished yet, but I thought that I would like to get
> > > some feedback. I still have to replace some of the numbers in the
> > > structure with defined values. I would also like to try and really
> > > probe the iic devices and not just assume that they are there.
> > 
> > I'm not sure whether it makes sense to support different boards in a
> > single binary (variations on a board design yes).  My experience is that
> > embedded applications are often cycle starved and giving up cycles for
> > flexibility like this is ok only for devel/bringup.  I suspect
> > compile-time configuration is preferable.
> > 
> > However if this flexibility is desirable it might be better to use
> > ivar's hung off the nexus.
> > 
> > 	Sam
> 
> I tend to agree. 
> I think one config file per board is not too much to handle, and detecting
> which board we're currently running can be difficult.
> 
> Olivier

I think my code changes are mostly in the attach routines or routines that
are used by them, so I don't think it will have an influence on run-time
speed. The biggest win for me would be that one could build a single
distro that would be able to run any of the two boards. They are so
similar, same cpu, 2 ethernets, 4 mini-pcis. But I guess in reality few
groups/companies will source more than one board for a product.

John
-- 
John Hay -- John.Hay at meraka.csir.co.za / jhay at FreeBSD.org