could be a reference.
Location of DFLs on a PCI Device
-===========================
+================================
The original method for finding a DFL on a PCI device assumed the start of the
first DFL to offset 0 of bar 0. If the first node of the DFL is an FME,
then further DFLs in the port(s) are specified in FME header registers.
Offset/BIR vendor specific registers for each DFL. Bits 2:0 of Offset/BIR register
indicates the BAR, and bits 31:3 form the 8 byte aligned offset where bits 2:0 are
zero.
+::
+----------------------------+
|31 Number of DFLS 0|