LoongArch extioi interrupt controller routes peripheral interrupt
to multiple CPUs, physical cpu id is used in interrupt routing table.
Here hotplug interface is added for extioi object, so that parent irq
line can be connected, and routing table can be added for new created
cpu.

Here only basic hotplug framework is added, it is stub function.

Signed-off-by: Bibo Mao <maobibo@loongson.cn>
---
 hw/intc/loongarch_extioi_common.c | 33 +++++++++++++++++++++++++++++++
 1 file changed, 33 insertions(+)

diff --git a/hw/intc/loongarch_extioi_common.c b/hw/intc/loongarch_extioi_common.c
index e3a38b318a..19e19a9f73 100644
--- a/hw/intc/loongarch_extioi_common.c
+++ b/hw/intc/loongarch_extioi_common.c
@@ -4,11 +4,37 @@
  * Copyright (C) 2024 Loongson Technology Corporation Limited
  */
 #include "qemu/osdep.h"
+#include "qemu/error-report.h"
 #include "qemu/module.h"
 #include "qapi/error.h"
 #include "hw/qdev-properties.h"
 #include "hw/intc/loongarch_extioi_common.h"
 #include "migration/vmstate.h"
+#include "target/loongarch/cpu.h"
+
+static void loongarch_extioi_cpu_plug(HotplugHandler *hotplug_dev,
+                                      DeviceState *dev, Error **errp)
+{
+    Object *obj = OBJECT(dev);
+
+    if (!object_dynamic_cast(obj, TYPE_LOONGARCH_CPU)) {
+        warn_report("LoongArch extioi: Invalid %s device type",
+                                       object_get_typename(obj));
+        return;
+    }
+}
+
+static void loongarch_extioi_cpu_unplug(HotplugHandler *hotplug_dev,
+                                        DeviceState *dev, Error **errp)
+{
+    Object *obj = OBJECT(dev);
+
+    if (!object_dynamic_cast(obj, TYPE_LOONGARCH_CPU)) {
+        warn_report("LoongArch extioi: Invalid %s device type",
+                                       object_get_typename(obj));
+        return;
+    }
+}
 
 static void loongarch_extioi_common_realize(DeviceState *dev, Error **errp)
 {
@@ -107,11 +133,14 @@ static void loongarch_extioi_common_class_init(ObjectClass *klass, void *data)
 {
     DeviceClass *dc = DEVICE_CLASS(klass);
     LoongArchExtIOICommonClass *lecc = LOONGARCH_EXTIOI_COMMON_CLASS(klass);
+    HotplugHandlerClass *hc = HOTPLUG_HANDLER_CLASS(klass);
 
     device_class_set_parent_realize(dc, loongarch_extioi_common_realize,
                                     &lecc->parent_realize);
     device_class_set_props(dc, extioi_properties);
     dc->vmsd = &vmstate_loongarch_extioi;
+    hc->plug = loongarch_extioi_cpu_plug;
+    hc->unplug = loongarch_extioi_cpu_unplug;
 }
 
 static const TypeInfo loongarch_extioi_common_types[] = {
@@ -121,6 +150,10 @@ static const TypeInfo loongarch_extioi_common_types[] = {
         .instance_size      = sizeof(LoongArchExtIOICommonState),
         .class_size         = sizeof(LoongArchExtIOICommonClass),
         .class_init         = loongarch_extioi_common_class_init,
+        .interfaces         = (InterfaceInfo[]) {
+            { TYPE_HOTPLUG_HANDLER },
+            { }
+        },
         .abstract           = true,
     }
 };
-- 
2.43.5