PCI multiple controller support in QNX


Could somebody explain or point to information on
how QNX PCI API (and server) supports architectures with multiple PCI
(multiple PCI bus trees).

pci_attach_device() uses struct pci_dev_info to define search criteria and
to return coordinates of found device.
What field of struct pci_dev_info indicates what controller/tree should be
scanned or on what controller/tree resides device found ?

pci_read_config32() has bus and dev_func arguments, but what about
controller/tree ?

Is there example of PCI server supporting multiple controllers ?