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, 5 insertions, 0 deletions

diff --git a/hw/ppc/e500.h b/hw/ppc/e500.h
index 621403bd24..3fd9f825ca 100644
--- a/hw/ppc/e500.h
+++ b/hw/ppc/e500.h
@@ -2,11 +2,16 @@
 #define PPCE500_H
 
 #include "hw/boards.h"
+#include "hw/platform-bus.h"
 
 typedef struct PPCE500MachineState {
     /*< private >*/
     MachineState parent_obj;
 
+    /* points to instance of TYPE_PLATFORM_BUS_DEVICE if
+     * board supports dynamic sysbus devices
+     */
+    PlatformBusDevice *pbus_dev;
 } PPCE500MachineState;
 
 typedef struct PPCE500MachineClass {