Can doorbell registers be configured for page sizes other than 4KB?

[drchristensen]

Reviewing the ionic driver shows that the doorbell registers (PCI BAR[1]) are configured as 4KB each. On the adapter I'm using, that results in 256 doorbell IDs for the 1MB BAR size. Does the hardware support page size values other than 4KB? Such as the 64KB page used on IBM POWER systems?

Actual support for an alternate page size would seem to require additional firmware changes to retrieve the system page size before responding to the "LIF init" command, but that's only possible if the underlying hardware supports such capability.

[jbradleysmith]

The device firmware has support for 4KB page size. The first doorbell page is used for ethernet queues and the additional doorbell pages are used for RDMA queue pairs.