PCI config space save-restore is not working with Hikey960


We have connected the PCIE device to Hikey960 board through PCIE M.2 M Key connector.
We want to turn OFF and turn ON the PCIE device which is controlled through some regulator, so before turning OFF PCI config space is saved and after turning ON config space will be restored back which is saved earlier, but restore of config space is not functioning properly because of which the PCIE enumeration fails and detecting as unknown device.
This method is working for us on another reference platform but same is not working with Hikey960.
Can somebody please help in resolving this issue?


Can somebody please comment on this??