On 04/11/2017 10:15 AM, abhijit wrote: > Here I am assuming, the completer ID will be device number and function > number that will eventually programmed in to device. In that case, my > question is, without first write, how read request(VENDOR ID read) is > serviced/routed?
You'll want to read about PCIe enumeration at boot time and how the BIOS walks the topology to assign these (which an OS may later re-number). In particular, read about ECAM for configuration. This uses memory mapped config space read/write accessors that target a memory address space under the control of the root complex. Jon.
