Re: [coreboot] v3 HT

[Marc Jones]

Carl-Daniel Hailfinger wrote:
> On 28.10.2008 00:40, ron minnich wrote:
> > On Mon, Oct 27, 2008 at 4:25 PM, Carl-Daniel Hailfinger
> >  wrote:
> > > The explanations by Tom and Marc made a few things clear for me:
> > > The physical HT structure is not what we want to model.
> > > The appearance of HT and topology in PCI config space is what matters.
> > > 18.0 is not a PCI bridge, don't pretend it is one
> > >
> > > With that in mind, I'd like to propose another dts.
> > > I know that it has its own quirks, but it can serve as a discussion point.
> >
> > I'm beginning to feel like we're thinking too much.
>
> We were trying to coax physical connections into the dts, but then we
> had to ignore them in the code because the logical connections and their
> placements were different.

This is the right track. Addressing is what is important for resource 
allocation. Later we can add a physical connection for ht that can be 
auto-generated runtime if we decide we want to know that as well.
> > The fact is that whether or not the three HT links are a bridge, there
> > is routing in there that makes each link logically the parent of a
> > different set of devices. do we call that a bridge?
>
> Do we ever walk the HT links explicitly in the code?

Not in device code. All that is done in Stage1 early init.
> > I don't know what to do with bus@1.
>
> I fully agree. That's the weakest point of my dts. We can place all
> those devices at bus 1, but for legacy reasons we may want to have them
> at bus 0. Our choice.

With the assumption that bus@X should be any number found that matches 
the device. Maybe remove the @X. I don't think it does anything. I think 
that this is more correct:

bus{
    pci@6,0 {
    	/config/("southbridge/amd/amd8111/pci.dts");
    	bus{
    		pci@0,0{
    		    /config/("southbridge/amd/amd8111/usb.dts");

Does the bus indicate anything? Would this work?

pci@6,0 {
    /config/("southbridge/amd/amd8111/pci.dts");
    pci@0,0{
    	/config/("southbridge/amd/amd8111/usb.dts");
> > ah well it's been a long day, will look at this later. For now let's
> > get myles patch in and try to see where that goes. I think I'm not
> > ready for this dts. But if myles wants to try it that's fine too.
>
> Sure, as long as the dts is not set in stone, I retract my NACK and
> encourage Myles to commit.

This isn't even set in jello, never mind stone! :)

Attached lspci from Serengeti (FAM10 CPU but buses should be the same).

Marc