Deriving from TYPE_SYS_BUS_DEVICE fixes the SoC object to be reset upon machine
reset. It also makes the SoC implementation not user-creatable which can trigger
the following crash:

  $ ./qemu-system-aarch64  -M virt -device fsl-imx8mp
  **
  ERROR:../../devel/qemu/tcg/tcg.c:1006:tcg_register_thread: assertion failed:
  (n < tcg_max_ctxs)
  Bail out! ERROR:../../devel/qemu/tcg/tcg.c:1006:tcg_register_thread:
  assertion failed: (n < tcg_max_ctxs)
  Aborted (core dumped)

Fixes: a4eefc69b237 "hw/arm: Add i.MX 8M Plus EVK board"
Reported-by: Thomas Huth <thuth@redhat.com>
Suggested-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Bernhard Beschow <shentey@gmail.com>
---
 include/hw/arm/fsl-imx8mp.h | 3 ++-
 hw/arm/fsl-imx8mp.c         | 2 +-
 hw/arm/imx8mp-evk.c         | 2 +-
 3 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/include/hw/arm/fsl-imx8mp.h b/include/hw/arm/fsl-imx8mp.h
index bc97fc416e..22fdc0d67c 100644
--- a/include/hw/arm/fsl-imx8mp.h
+++ b/include/hw/arm/fsl-imx8mp.h
@@ -26,6 +26,7 @@
 #include "hw/timer/imx_gpt.h"
 #include "hw/usb/hcd-dwc3.h"
 #include "hw/watchdog/wdt_imx2.h"
+#include "hw/sysbus.h"
 #include "qom/object.h"
 #include "qemu/units.h"
 
@@ -49,7 +50,7 @@ enum FslImx8mpConfiguration {
 };
 
 struct FslImx8mpState {
-    DeviceState    parent_obj;
+    SysBusDevice   parent_obj;
 
     ARMCPU             cpu[FSL_IMX8MP_NUM_CPUS];
     GICv3State         gic;
diff --git a/hw/arm/fsl-imx8mp.c b/hw/arm/fsl-imx8mp.c
index c3f6da6322..82edf61082 100644
--- a/hw/arm/fsl-imx8mp.c
+++ b/hw/arm/fsl-imx8mp.c
@@ -702,7 +702,7 @@ static void fsl_imx8mp_class_init(ObjectClass *oc, void *data)
 static const TypeInfo fsl_imx8mp_types[] = {
     {
         .name = TYPE_FSL_IMX8MP,
-        .parent = TYPE_DEVICE,
+        .parent = TYPE_SYS_BUS_DEVICE,
         .instance_size = sizeof(FslImx8mpState),
         .instance_init = fsl_imx8mp_init,
         .class_init = fsl_imx8mp_class_init,
diff --git a/hw/arm/imx8mp-evk.c b/hw/arm/imx8mp-evk.c
index e1a21e52f9..f17d5db466 100644
--- a/hw/arm/imx8mp-evk.c
+++ b/hw/arm/imx8mp-evk.c
@@ -37,7 +37,7 @@ static void imx8mp_evk_init(MachineState *machine)
     s = FSL_IMX8MP(object_new(TYPE_FSL_IMX8MP));
     object_property_add_child(OBJECT(machine), "soc", OBJECT(s));
     object_property_set_uint(OBJECT(s), "fec1-phy-num", 1, &error_fatal);
-    qdev_realize_and_unref(DEVICE(s), NULL, &error_fatal);
+    sysbus_realize_and_unref(SYS_BUS_DEVICE(s), &error_fatal);
 
     memory_region_add_subregion(get_system_memory(), FSL_IMX8MP_RAM_START,
                                 machine->ram);
-- 
2.49.0