quoted

OK. Sorry, I have one last question, because domain will be used to calculate the address used to
access PCI hardware config registers. So if DTS file doesn't report the domain, how do we know
we would access the right registers when we use the auto increment domain vaule ?
Has there a mechanism to make sure system can access the correct registers by the domain ?

I think you're referring to config access via ECAM (PCIe r3.0, sec
7.2.2).  In that case, I don't think the domain should be used to
compute the memory-mapped configuration address.  Each host bridge is
in exactly one domain, and each host bridge has an associated ECAM
area base.  The address calculation uses the bus number, device
number, function number, and register number to compute an offset into
the ECAM area.

So as long as the DT tells you the ECAM information for each host
bridge, that should be sufficient.  The domain number is then just a
Linux convenience and is not tied to the platform as it is on ia64.

Hi Bjorn, you are right, thanks for your detailed explanation! :)

Thanks!
Yijing.

Bjorn

.

-- 
Thanks!
Yijing