[coreboot] domain vs device statictree order

Myles Watson mylesgw at gmail.com
Wed Jan 7 00:19:06 CET 2009


On Tue, Jan 6, 2009 at 4:13 PM, Marc Jones <marcj303 at gmail.com> wrote:

> I agree it is parents before siblings but I thought it looked more
> like a problem with the statictree. I must not understand .next.
>
> from http://pastebin.ca/1301081
>
> dev_apic_0 has a .sibling = &dev_domain_0 and .next = &dev_domain_0_pci_1_0
>
> Then later in the last device domain dev_domain_0_pci_f_2 has a .next
> = &dev_domain_0.
>
> I would expect .sibling and .next to point to the &dev_domain_0 and
> then dev_domain_0 to have .next = &dev_domain_0_pci_1_0

Yes.  I would too.  It's that way because parents get defined after
children.  When the tree is being read, the full parent is not read
(we don't get to the closing brace) until after we read all the
children.  It seems confusing to me, but it is the way dts works.

> dev_cpus looks like I would expect .sibling = &dev_apic_0 and .next =
> &dev_apic_0.
> dev_domain_0_pci_f_0 also has the same .sibling and .next.

Yes.  Children are complete before their sibling is read in, so all
devices with childless siblings have the same .sibling and .next.

I hope that doesn't sound like blather :)

Thanks,
Myles




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