[Qemu-arm] [PATCH v2 15/16] hw/arm/mps2: Use object_initialize_child for correct reference counting

[Philippe Mathieu-Daudé]

As explained in commit aff39be0ed97:

  Both functions, object_initialize() and object_property_add_child()
  increase the reference counter of the new object, so one of the
  references has to be dropped afterwards to get the reference
  counting right. Otherwise the child object will not be properly
  cleaned up when the parent gets destroyed.
  Thus let's use now object_initialize_child() instead to get the
  reference counting here right.

This patch was generated using the following Coccinelle script:

 @use_sysbus_init_child_obj_missing_parent@
 expression child_ptr;
 expression child_type;
 expression child_size;
 @@
 -   object_initialize(child_ptr, child_size, child_type);
     ...
 -   qdev_set_parent_bus(DEVICE(child_ptr), sysbus_get_default());
     ...
 ?-  object_unref(OBJECT(child_ptr));
 +   sysbus_init_child_obj(OBJECT(PARENT_OBJ), "CHILD_NAME", child_ptr,
 +                         child_size, child_type);

We let the MPS2 boards adopt the cpu core, the FPGA and the SCC children.

While the object_initialize() function doesn't take an
'Error *errp' argument, the object_initialize_child() does.
Since this code is used when a machine is created (and is not
yet running), we deliberately choose to use the &error_abort
argument instead of ignoring errors if an object creation failed.
This choice also matches when using sysbus_init_child_obj(),
since its code is:

  void sysbus_init_child_obj(Object *parent,
                             const char *childname, void *child,
                             size_t childsize, const char *childtype)
  {
      object_initialize_child(parent, childname, child, childsize,
                              childtype, &error_abort, NULL);

      qdev_set_parent_bus(DEVICE(child), sysbus_get_default());
  }

Suggested-by: Eduardo Habkost <address@hidden>
Inspired-by: Thomas Huth <address@hidden>
Signed-off-by: Philippe Mathieu-Daudé <address@hidden>
---
 hw/arm/mps2-tz.c | 8 ++++----
 hw/arm/mps2.c    | 8 ++++----
 2 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/hw/arm/mps2-tz.c b/hw/arm/mps2-tz.c
index 7832408bb70..82dce1a7b38 100644
--- a/hw/arm/mps2-tz.c
+++ b/hw/arm/mps2-tz.c
@@ -214,9 +214,9 @@ static MemoryRegion *make_scc(MPS2TZMachineState *mms, void 
*opaque,
     DeviceState *sccdev;
     MPS2TZMachineClass *mmc = MPS2TZ_MACHINE_GET_CLASS(mms);
 
-    object_initialize(scc, sizeof(mms->scc), TYPE_MPS2_SCC);
+    sysbus_init_child_obj(OBJECT(mms), "scc", scc,
+                          sizeof(mms->scc), TYPE_MPS2_SCC);
     sccdev = DEVICE(scc);
-    qdev_set_parent_bus(sccdev, sysbus_get_default());
     qdev_prop_set_uint32(sccdev, "scc-cfg4", 0x2);
     qdev_prop_set_uint32(sccdev, "scc-aid", 0x00200008);
     qdev_prop_set_uint32(sccdev, "scc-id", mmc->scc_id);
@@ -229,8 +229,8 @@ static MemoryRegion *make_fpgaio(MPS2TZMachineState *mms, 
void *opaque,
 {
     MPS2FPGAIO *fpgaio = opaque;
 
-    object_initialize(fpgaio, sizeof(mms->fpgaio), TYPE_MPS2_FPGAIO);
-    qdev_set_parent_bus(DEVICE(fpgaio), sysbus_get_default());
+    sysbus_init_child_obj(OBJECT(mms), "fpgaio", fpgaio,
+                          sizeof(mms->fpgaio), TYPE_MPS2_FPGAIO);
     object_property_set_bool(OBJECT(fpgaio), true, "realized", &error_fatal);
     return sysbus_mmio_get_region(SYS_BUS_DEVICE(fpgaio), 0);
 }
diff --git a/hw/arm/mps2.c b/hw/arm/mps2.c
index 54b7395849f..ecb8ae3c14c 100644
--- a/hw/arm/mps2.c
+++ b/hw/arm/mps2.c
@@ -174,9 +174,9 @@ static void mps2_common_init(MachineState *machine)
         g_assert_not_reached();
     }
 
-    object_initialize(&mms->armv7m, sizeof(mms->armv7m), TYPE_ARMV7M);
+    sysbus_init_child_obj(OBJECT(mms), "armv7m", &mms->armv7m,
+                          sizeof(mms->armv7m), TYPE_ARMV7M);
     armv7m = DEVICE(&mms->armv7m);
-    qdev_set_parent_bus(armv7m, sysbus_get_default());
     switch (mmc->fpga_type) {
     case FPGA_AN385:
         qdev_prop_set_uint32(armv7m, "num-irq", 32);
@@ -308,9 +308,9 @@ static void mps2_common_init(MachineState *machine)
                        qdev_get_gpio_in(armv7m, 10));
     sysbus_mmio_map(SYS_BUS_DEVICE(&mms->dualtimer), 0, 0x40002000);
 
-    object_initialize(&mms->scc, sizeof(mms->scc), TYPE_MPS2_SCC);
+    sysbus_init_child_obj(OBJECT(mms), "scc", &mms->scc,
+                          sizeof(mms->scc), TYPE_MPS2_SCC);
     sccdev = DEVICE(&mms->scc);
-    qdev_set_parent_bus(sccdev, sysbus_get_default());
     qdev_prop_set_uint32(sccdev, "scc-cfg4", 0x2);
     qdev_prop_set_uint32(sccdev, "scc-aid", 0x00200008);
     qdev_prop_set_uint32(sccdev, "scc-id", mmc->scc_id);
-- 
2.20.1