ppc/pnv: add phb-id/chip-id PnvPHB4RootBus properties

The same rationale provided in the PHB3 bus case applies here.

Note: we could have merged both buses in a single object, like we did
with the root ports, and spare some boilerplate. The reason we opted to
preserve both buses objects is twofold:

- there's not user side advantage in doing so. Unifying the root ports
presents a clear user QOL change when we enable user created devices back.
The buses objects, aside from having a different QOM name, is transparent
to the user;

- we leave a door opened in case we want to increase the root port limit
for phb4/5 later on without having to deal with phb3 code.

Reviewed-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Reviewed-by: Frederic Barrat <fbarrat@linux.ibm.com>
Message-Id: <20220811163950.578927-3-danielhb413@gmail.com>

hw/pci-host/pnv_phb4.c

@@ -1551,6 +1551,12 @@ void pnv_phb4_bus_init(DeviceState *dev, PnvPHB4 *phb)
                                      pnv_phb4_set_irq, pnv_phb4_map_irq, phb,
                                      &phb->pci_mmio, &phb->pci_io,
                                      0, 4, TYPE_PNV_PHB4_ROOT_BUS);
+
+    object_property_set_int(OBJECT(pci->bus), "phb-id", phb->phb_id,
+                            &error_abort);
+    object_property_set_int(OBJECT(pci->bus), "chip-id", phb->chip_id,
+                            &error_abort);
+
     pci_setup_iommu(pci->bus, pnv_phb4_dma_iommu, phb);
     pci->bus->flags |= PCI_BUS_EXTENDED_CONFIG_SPACE;
 }
@@ -1708,10 +1714,55 @@ static const TypeInfo pnv_phb5_type_info = {
     .instance_size = sizeof(PnvPHB4),
 };
 
+static void pnv_phb4_root_bus_get_prop(Object *obj, Visitor *v,
+                                       const char *name,
+                                       void *opaque, Error **errp)
+{
+    PnvPHB4RootBus *bus = PNV_PHB4_ROOT_BUS(obj);
+    uint64_t value = 0;
+
+    if (strcmp(name, "phb-id") == 0) {
+        value = bus->phb_id;
+    } else {
+        value = bus->chip_id;
+    }
+
+    visit_type_size(v, name, &value, errp);
+}
+
+static void pnv_phb4_root_bus_set_prop(Object *obj, Visitor *v,
+                                       const char *name,
+                                       void *opaque, Error **errp)
+
+{
+    PnvPHB4RootBus *bus = PNV_PHB4_ROOT_BUS(obj);
+    uint64_t value;
+
+    if (!visit_type_size(v, name, &value, errp)) {
+        return;
+    }
+
+    if (strcmp(name, "phb-id") == 0) {
+        bus->phb_id = value;
+    } else {
+        bus->chip_id = value;
+    }
+}
+
 static void pnv_phb4_root_bus_class_init(ObjectClass *klass, void *data)
 {
     BusClass *k = BUS_CLASS(klass);
 
+    object_class_property_add(klass, "phb-id", "int",
+                              pnv_phb4_root_bus_get_prop,
+                              pnv_phb4_root_bus_set_prop,
+                              NULL, NULL);
+
+    object_class_property_add(klass, "chip-id", "int",
+                              pnv_phb4_root_bus_get_prop,
+                              pnv_phb4_root_bus_set_prop,
+                              NULL, NULL);
+
     /*
      * PHB4 has only a single root complex. Enforce the limit on the
      * parent bus

include/hw/pci-host/pnv_phb4.h

@@ -45,7 +45,17 @@ typedef struct PnvPhb4DMASpace {
     QLIST_ENTRY(PnvPhb4DMASpace) list;
 } PnvPhb4DMASpace;
 
+/*
+ * PHB4 PCIe Root Bus
+ */
 #define TYPE_PNV_PHB4_ROOT_BUS "pnv-phb4-root"
+struct PnvPHB4RootBus {
+    PCIBus parent;
+
+    uint32_t chip_id;
+    uint32_t phb_id;
+};
+OBJECT_DECLARE_SIMPLE_TYPE(PnvPHB4RootBus, PNV_PHB4_ROOT_BUS)
 
 /*
  * PHB4 PCIe Host Bridge for PowerNV machines (POWER9)