cgd@netbsd.org (Chris G. Demetriou) writes:

> It's a three pass thing, the way i see it:
> 
> * You go down the PCI bus hierarchy figuring out where and how big
> the devices are.
> 
> * You then go back up the PCI bus hierarchy figuring out how to pack
> devices into 'bins' (the windows provided by the bridges).
> 
> * You then go badn down the PCI bus hierarchy actually filling in
> bridges configuration registers and devices' BARs.
> 
> (There's also the issue of assigning secondary/subordinate bus
> numbers, etc., which is a similar thing.)
> 
> Really, since many modern PCI BIOSes (on PCs 8-) don't do PCI address
> space assignment, we have to do it.
> 
> We have to have the same code to cope with the bin-packing necessary
> for CardBus cards and devices behind them.

This is somewhat off-topic, but.

One thing I've never fully understood is how this (PCI configuration)
is supposed to work if you attach a cardbus-pci bridge; especially the
pci-bus numbering. Do you have to redo the whole configuration if this
happens, or can you take some shortcut? Guess I'll have to read a book
about PCI.

/Johan