Documentation/devicetree/bindings/pci/pci.txt

   1 PCI bus bridges have standardized Device Tree bindings:
   2
   3 PCI Bus Binding to: IEEE Std 1275-1994
   4 http://www.openfirmware.org/ofwg/bindings/pci/pci2_1.pdf
   5
   6 And for the interrupt mapping part:
   7
   8 Open Firmware Recommended Practice: Interrupt Mapping
   9 http://www.openfirmware.org/1275/practice/imap/imap0_9d.pdf