PCI Configuration Space

[Krueger, Jon]

I found an interesting "problem" with the IXP1200.

When doing Type 0/1 configuration reads with the IXP, 
any attempt to access devices using AD26-AD31 for their
IDSEL decoding will produce nasty results.

With VxWorks, you'll get an exception, killing process execution.
With the custom OS I'm running now, I drop into the debugger and the 
ARM PC is off in deep space...   :-(

This may be a design decision by the IXP engineers.  They do support
a full 10 devices, but they assume that the devices will be decoded
within the config space of AD11-AD25.  I'm guessing a bit here, but
it seems that this is the case.

There are SBCs and "passive" backplanes which hardwire device IDSELs to the
higher areas of config space AD26-AD31.

Something to watch out for...


jk



> Jon Krueger
> Senior Engineer
> Intel Corporation
> Network Equipment Division
> 
> 13280 Evening Creek Drive
> San Diego, CA  92128
> (858) 391-1710
> jon.krueger at intel.com
> 
>