H experts,
I have one question about PCIe enumeration.
Our system is
Host CPU.PCIe -------------------- PCIe Bridge or Switch ---------------- Keystone1 PCI or KS2 PCIe
When all the 3 devices are powered on, enumeraion will be done.
In this status, if KS1 or KS2 is reset, then enumeraion will be re-done, is it right?
I want to know how & why ic can be done.
From the below site, I can see following description. But I don't know well if "power-off' means power-off of EP. Resetting of RC(that is, host) will need re-configuration of BARs(and also other things).. Does resetting of EP need also re-numeration? Then how does RC know that EP is powered off? RC is monitering any PCIe signal from EP?
http://en.wikipedia.org/wiki/PCI_configuration_space
At this point, the BIOS or operating system will program the memory-mapped and I/O port addresses into the device's BAR configuration register. These addresses stay valid as long as the system remains turned on. Upon power-off, all these settingsare lost and the procedure is repeated next time the system is powered back on. Since this entire process is fully automated, the user is spared the task of configuring any newly added hardware manually by changing DIP switches on the cards themselves. This automatic device discovery and address space assignment is how plug and play is implemented.
B.Regards,
Devin