ppce500_pci: QOM'ify e500 PCI host bridge

Introduce type constant and cast macro. Avoid accessing parent fields
directly.

Signed-off-by: Andreas Färber <afaerber@suse.de>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

hw/ppce500_pci.c

@@ -72,8 +72,14 @@ struct pci_inbound {
     uint32_t piwar;
 };
 
+#define TYPE_PPC_E500_PCI_HOST_BRIDGE "e500-pcihost"
+
+#define PPC_E500_PCI_HOST_BRIDGE(obj) \
+    OBJECT_CHECK(PPCE500PCIState, (obj), TYPE_PPC_E500_PCI_HOST_BRIDGE)
+
 struct PPCE500PCIState {
     PCIHostState pci_state;
+
     struct pci_outbound pob[PPCE500_PCI_NR_POBS];
     struct pci_inbound pib[PPCE500_PCI_NR_PIBS];
     uint32_t gasket_time;
@@ -310,17 +316,17 @@ static int e500_pcihost_initfn(SysBusDevice *dev)
     MemoryRegion *address_space_mem = get_system_memory();
     MemoryRegion *address_space_io = get_system_io();
 
-    h = FROM_SYSBUS(PCIHostState, sysbus_from_qdev(dev));
-    s = DO_UPCAST(PPCE500PCIState, pci_state, h);
+    h = FROM_SYSBUS(PCIHostState, dev);
+    s = PPC_E500_PCI_HOST_BRIDGE(dev);
 
     for (i = 0; i < ARRAY_SIZE(s->irq); i++) {
         sysbus_init_irq(dev, &s->irq[i]);
     }
 
-    b = pci_register_bus(&s->pci_state.busdev.qdev, NULL, mpc85xx_pci_set_irq,
+    b = pci_register_bus(DEVICE(dev), NULL, mpc85xx_pci_set_irq,
                          mpc85xx_pci_map_irq, s->irq, address_space_mem,
                          address_space_io, PCI_DEVFN(0x11, 0), 4);
-    s->pci_state.bus = b;
+    h->bus = b;
 
     pci_create_simple(b, 0, "e500-host-bridge");
 
@@ -367,7 +373,7 @@ static void e500_pcihost_class_init(ObjectClass *klass, void *data)
 }
 
 static const TypeInfo e500_pcihost_info = {
-    .name          = "e500-pcihost",
+    .name          = TYPE_PPC_E500_PCI_HOST_BRIDGE,
     .parent        = TYPE_SYS_BUS_DEVICE,
     .instance_size = sizeof(PPCE500PCIState),
     .class_init    = e500_pcihost_class_init,