ppc/pnv: add phb-id/chip-id PnvPHB3RootBus properties

We rely on the phb-id and chip-id, which are PHB properties, to assign
chassis and slot to the root port. For default devices this is no big
deal: the root port is being created under pnv_phb_realize() and the
values are being passed on via the 'index' and 'chip-id' of the
pnv_phb_attach_root_port() helper.

If we want to implement user created root ports we have a problem. The
user created root port will not be aware of which PHB it belongs to,
unless we're willing to violate QOM best practices and access the PHB
via dev->parent_bus->parent. What we can do is to access the root bus
parent bus.

Since we're already assigning the root port as QOM child of the bus, and
the bus is initiated using PHB properties, let's add phb-id and chip-id
as properties of the bus. This will allow us trivial access to them, for
both user-created and default root ports, without doing anything too
shady with QOM.

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: <20220811163950.578927-2-danielhb413@gmail.com>

hw/pci-host/pnv_phb3.c

@@ -1006,6 +1006,11 @@ void pnv_phb3_bus_init(DeviceState *dev, PnvPHB3 *phb)
                                      &phb->pci_mmio, &phb->pci_io,
                                      0, 4, TYPE_PNV_PHB3_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_phb3_dma_iommu, phb);
 }
 
@@ -1105,10 +1110,55 @@ static const TypeInfo pnv_phb3_type_info = {
     .instance_init = pnv_phb3_instance_init,
 };
 
+static void pnv_phb3_root_bus_get_prop(Object *obj, Visitor *v,
+                                       const char *name,
+                                       void *opaque, Error **errp)
+{
+    PnvPHB3RootBus *bus = PNV_PHB3_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_phb3_root_bus_set_prop(Object *obj, Visitor *v,
+                                       const char *name,
+                                       void *opaque, Error **errp)
+
+{
+    PnvPHB3RootBus *bus = PNV_PHB3_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_phb3_root_bus_class_init(ObjectClass *klass, void *data)
 {
     BusClass *k = BUS_CLASS(klass);
 
+    object_class_property_add(klass, "phb-id", "int",
+                              pnv_phb3_root_bus_get_prop,
+                              pnv_phb3_root_bus_set_prop,
+                              NULL, NULL);
+
+    object_class_property_add(klass, "chip-id", "int",
+                              pnv_phb3_root_bus_get_prop,
+                              pnv_phb3_root_bus_set_prop,
+                              NULL, NULL);
+
     /*
      * PHB3 has only a single root complex. Enforce the limit on the
      * parent bus

include/hw/pci-host/pnv_phb3.h

@@ -104,9 +104,16 @@ struct PnvPBCQState {
 };
 
 /*
- * PHB3 PCIe Root port
+ * PHB3 PCIe Root Bus
  */
 #define TYPE_PNV_PHB3_ROOT_BUS "pnv-phb3-root"
+struct PnvPHB3RootBus {
+    PCIBus parent;
+
+    uint32_t chip_id;
+    uint32_t phb_id;
+};
+OBJECT_DECLARE_SIMPLE_TYPE(PnvPHB3RootBus, PNV_PHB3_ROOT_BUS)
 
 /*
  * PHB3 PCIe Host Bridge for PowerNV machines (POWER8)