when is pci_dev->resource values are filled?

[Chan Kim]

Hi, all

When initializing a PCI device, during the pci_driver's probe function,
pci_request_region is called.
Inside the pci_request_region, it is just calling request_region with the
values in pci_dev->resource[bar].start and end.
But when is this pci->dev->resource values filled? Is it done by the BIOS(or
UEFI) before linux boots? 
Probably not because this pci_dev struct is from linux and should be filled
by linux code and I couldn't find where it's done.

Chan Kim