[OpenBIOS] [sparc64] Problematic pci at 0 and pci nodes in the device tree

Jakub Jermar jakub at jermar.eu
Sun Jan 18 18:55:34 CET 2009

Blue Swirl wrote:
> On 1/16/09, Jakub Jermar <jakub at jermar.eu> wrote:
>> Hi,
>>  I have the following problem with the OpenBIOS device tree (the current Qemu version):
>>  In the root directory, there are currently two pci nodes:
>>  ffd97778 pci at 0
>>  ffd98808 pci
>>  The "screen" alias is defined as:
>>  /pci/pci/pci/QEMU,VGA
>>  When HelenOS attempts to lookup this path, it fails, because it matches /pci instead
>>  of /pci at 0 and /pci does not have any children. HelenOS is normally designed to cope
>>  with ambiguous node names, but in this case the /pci node matches and sends it to the
>>  wrong direction. I think the "screen" alias should be either defined using the
>>  non-ambiguous pci at 0 path components or the /pci node should not exist at all.
>>  Can you confirm this is a problem in the tree?
> Yes, there is a duplicate for some reason for most PCI devices. Also
> the address is 0, except for IDE and serial.

After some recent changes in Qemu, this is no longer a problem and HelenOS finds
the QEMU,VGA node.

The properties needed to find the physical address of the framebuffer seem to
be still wrong. Is this fixed in the upstream version of OpenBIOS (I still haven't
figured out how to build openbios :-()? Basically what is needed is the reg property
in the screen node and ranges properties in all the nodes above screen up to the
root. I believe the address property is normally used to hold a virtual address
valid for ofw-managed mappings (not the physical address), but I may be wrong.


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