spapr_pci: create DRConnectors for each PCI slot during PHB realize

These will be used to support hotplug/unplug of PCI devices to the PCI
bus associated with a particular PHB.

Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
spapr_pci: populate DRC dt entries for PHBs

Reserve 32 entries of type PCI in each PHB's initial FDT. This
advertises to guests that each PHB is DR-capable device with
physical hotpluggable slots. This is necessary for allowing
hotplugging of devices to it later via bus rescan or guest rpaphp
hotplug module.

Each entry is assigned a name of "Slot <<bus_idx>*32 +1>",
advertised as a hotpluggable PCI slot, and assigned to power domain
-1 to indicate to the guest that power management is handled by the
hardware.

This models a DR-capable PCI expansion device attached to a host/lpar
via a single PHB with 32 physical hotpluggable slots (as opposed to a
virtual bridge device with external management console). Hotplug will
be handled by the guest via bus rescan or the rpaphp hotplug module.

Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
pci: allow 0 address for PCI IO regions

Some kernels program a 0 address for io regions. PCI 3.0 spec
section 6.2.5.1 doesn't seem to disallow this.

Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
pci: make pci_bar useable outside pci.c

Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
spapr_pci: enable basic hotplug operations

This enables hotplug for PHB bridges. Upon hotplug we generate the
OF-nodes required by PAPR specification and IEEE 1275-1994
"PCI Bus Binding to Open Firmware" for the device.

We associate the corresponding FDT for these nodes with the DrcEntry
corresponding to the slot, which will be fetched via
ibm,configure-connector RTAS calls by the guest as described by PAPR
specification. The FDT is cleaned up in the case of unplug.

Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
spapr_pci: emit hotplug add/remove events during hotplug

This uses extension of existing EPOW interrupt/event mechanism
to notify userspace tools like librtas/drmgr to handle
in-guest configuration/cleanup operations in response to
device_add/device_del.

Userspace tools that don't implement this extension will need
to be run manually in response/advance of device_add/device_del,
respectively.

Signed-off-by: Tyrel Datwyler <tyreld@linux.vnet.ibm.com>
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
*spapr: enable PHB hotplug for pseries-2.3

Introduce an sPAPRMachineClass sub-class of MachineClass to
handle sPAPR-specific machine configuration properties.

The 'dr_phb_enabled' field of that class can be set as
part of machine-specific init code, and is then propagated
to sPAPREnvironment to conditional enable creation of DRC
objects and device-tree description to facilitate hotplug
of PHBs.

Since we can't migrate this state to older machine types,
default the option to false and only enable it for new
machine types.

Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
*spapr: create DR connectors for PHBs and register reset hooks

Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
*spapr: populate PHB DRC entries for root DT node

This add entries to the root OF node to advertise our PHBs as being
DR-capable in accordance with PAPR specification.

Signed-off-by: Nathan Fontenot <nfont@linux.vnet.ibm.com>
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
spapr_pci: add ibm,my-drc-index property for PHB hotplug