PCI configuration question

[Eric W. Biederman]

Liu Tao <liutao at safe-mail.net> writes:

> Hello all,
> 
> In the LinuxBIOS-AMD64 document the author explains the "pci" keyword
>  >  The first occurrence of the pci keyword tells LinuxBIOS where the bridge
> device start,
>  >  relative to PCI configuration space used by the bridge. The following
> occurences of
>  >  the pci keyword describe the provided devices.
> 
> then gives an example
>  >  northbridge amd/amdk8 "mc1"
>  >          pci 0:19.0
>  >          pci 0:19.0
>  >          pci 0:19.0
>  >          pci 0:19.1
>  >          pci 0:19.2
>  >          pci 0:19.3
>  >  end
> 
> I'm not clear why the example repeate "pci 0:19.0" three times?
> I noticed in chip.c the chip_enumerate() function checks the same path
>  >        identical_paths = (i > 0) && (path_eq(&chip->path[i - 1].path,
> &chip->path[i].path));
> but I can't find out the real intent.

Because I need some way of showing there are 3 hypertransport links.
With just one I don't have enough places to hang the devices off of.
 
> Another question maybe related to the former one is, in "device" structure
> what does the "link[MAX_LINKS]" and "links" member describe?
> Does "link[MAX_LINKS]" describes the secondary or subordinate bus of a bridge
> device?
> Why MAX_LINKS is defined to 3?

Because that is the largest number of links I have ever had hanging off of
one device.

Eric