platform-bus-device: use device plug callback instead of machine_done notifier

platform-bus were using machine_done notifier to get and map
(assign irq/mmio resources) dynamically added sysbus devices
after all '-device' options had been processed.
That however creates non obvious dependencies on ordering of
machine_done notifiers and requires carefull line juggling
to keep it working. For example see comment above
create_platform_bus() and 'straitforward' arm_load_kernel()
had to converted to machine_done notifier and that lead to
yet another machine_done notifier to keep it working
arm_register_platform_bus_fdt_creator().

Instead of hiding resource assignment in platform-bus-device
to magically initialize sysbus devices, use device plug
callback and assign resources explicitly at board level
at the moment each -device option is being processed.

That adds a bunch of machine declaration boiler plate to
e500plat board, similar to ARM/x86 but gets rid of hidden
machine_done notifier and would allow to remove the dependent
notifiers in ARM code simplifying it and making code flow
easier to follow.

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Acked-by: David Gibson <david@gibson.dropbear.id.au>
Message-id: 1525691524-32265-3-git-send-email-imammedo@redhat.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

1 files changed, 31 insertions, 0 deletions

diff --git a/hw/ppc/e500plat.c b/hw/ppc/e500plat.c
index f69aadb666..1a469ba69f 100644
--- a/hw/ppc/e500plat.c
+++ b/hw/ppc/e500plat.c
@@ -43,13 +43,40 @@ static void e500plat_init(MachineState *machine)
     ppce500_init(machine);
 }
 
+static void e500plat_machine_device_plug_cb(HotplugHandler *hotplug_dev,
+                                            DeviceState *dev, Error **errp)
+{
+    PPCE500MachineState *pms = PPCE500_MACHINE(hotplug_dev);
+
+    if (pms->pbus_dev) {
+        if (object_dynamic_cast(OBJECT(dev), TYPE_SYS_BUS_DEVICE)) {
+            platform_bus_link_device(pms->pbus_dev, SYS_BUS_DEVICE(dev));
+        }
+    }
+}
+
+static
+HotplugHandler *e500plat_machine_get_hotpug_handler(MachineState *machine,
+                                                    DeviceState *dev)
+{
+    if (object_dynamic_cast(OBJECT(dev), TYPE_SYS_BUS_DEVICE)) {
+        return HOTPLUG_HANDLER(machine);
+    }
+
+    return NULL;
+}
+
 #define TYPE_E500PLAT_MACHINE  MACHINE_TYPE_NAME("ppce500")
 
 static void e500plat_machine_class_init(ObjectClass *oc, void *data)
 {
     PPCE500MachineClass *pmc = PPCE500_MACHINE_CLASS(oc);
+    HotplugHandlerClass *hc = HOTPLUG_HANDLER_CLASS(oc);
     MachineClass *mc = MACHINE_CLASS(oc);
 
+    mc->get_hotplug_handler = e500plat_machine_get_hotpug_handler;
+    hc->plug = e500plat_machine_device_plug_cb;
+
     pmc->pci_first_slot = 0x1;
     pmc->pci_nr_slots = PCI_SLOT_MAX - 1;
     pmc->fixup_devtree = e500plat_fixup_devtree;
@@ -77,6 +104,10 @@ static const TypeInfo e500plat_info = {
     .name          = TYPE_E500PLAT_MACHINE,
     .parent        = TYPE_PPCE500_MACHINE,
     .class_init    = e500plat_machine_class_init,
+    .interfaces    = (InterfaceInfo[]) {
+         { TYPE_HOTPLUG_HANDLER },
+         { }
+    }
 };
 
 static void e500plat_register_types(void)