This supports PCI surprise hotplug. The design is highlighted as
below:
* The PCI slot's surprise hotplug capability is exposed through
device node property "ibm,slot-surprise-pluggable", meaning
PCI surprise hotplug will be disabled if skiboot doesn't support
it yet.
* The interrupt because of presence or link state change is raised
on surprise hotplug event. One event is allocated and queued to
the PCI slot for workqueue to pick it up and process in serialized
fashion. The code flow for surprise hotplug is same to that for
managed hotplug except: the affected PEs are put into frozen state
to avoid unexpected EEH error reporting in surprise hot remove path.
Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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