[Qemu-devel] [RFC PATCH v2 04/12] make Device and Bus Resettable

[Damien Hedde]

This add Resettable interface implementation for both Bus and Device.
The init phase default implementation is to call the legacy reset
handler.

qdev/bus_reset_all implementations are modified to use the new
device_reset / bus_reset function.

Signed-off-by: Damien Hedde <address@hidden>
---
 hw/core/bus.c          | 60 ++++++++++++++++++++++++++++++++++++++
 hw/core/qdev.c         | 65 +++++++++++++++++++++++++++++++++++-------
 include/hw/qdev-core.h | 63 ++++++++++++++++++++++++++++++++++------
 tests/Makefile.include |  1 +
 4 files changed, 170 insertions(+), 19 deletions(-)

diff --git a/hw/core/bus.c b/hw/core/bus.c
index e09843f6ab..c731e5cac7 100644
--- a/hw/core/bus.c
+++ b/hw/core/bus.c
@@ -21,6 +21,7 @@
 #include "qemu-common.h"
 #include "hw/qdev.h"
 #include "qapi/error.h"
+#include "hw/resettable.h"
 
 void qbus_set_hotplug_handler(BusState *bus, Object *handler, Error **errp)
 {
@@ -67,6 +68,54 @@ int qbus_walk_children(BusState *bus,
     return 0;
 }
 
+void bus_reset(BusState *bus, bool cold)
+{
+    resettable_reset(OBJECT(bus), cold);
+}
+
+bool bus_is_resetting(BusState *bus)
+{
+    return (bus->resetting != 0);
+}
+
+static uint32_t bus_get_reset_count(Object *obj)
+{
+    BusState *bus = BUS(obj);
+    return bus->resetting;
+}
+
+static uint32_t bus_increment_reset_count(Object *obj)
+{
+    BusState *bus = BUS(obj);
+    return ++bus->resetting;
+}
+
+static uint32_t bus_decrement_reset_count(Object *obj)
+{
+    BusState *bus = BUS(obj);
+    return --bus->resetting;
+}
+
+static void bus_foreach_reset_child(Object *obj, void (*func)(Object *))
+{
+    BusState *bus = BUS(obj);
+    BusChild *kid;
+
+    QTAILQ_FOREACH(kid, &bus->children, sibling) {
+        func(OBJECT(kid->child));
+    }
+}
+
+static void bus_reset_init_phase(Object *obj, bool cold)
+{
+    BusState *bus = BUS(obj);
+    BusClass *bc = BUS_GET_CLASS(obj);
+
+    if (bc->reset) {
+        bc->reset(bus);
+    }
+}
+
 static void qbus_realize(BusState *bus, DeviceState *parent, const char *name)
 {
     const char *typename = object_get_typename(OBJECT(bus));
@@ -204,9 +253,16 @@ static char *default_bus_get_fw_dev_path(DeviceState *dev)
 static void bus_class_init(ObjectClass *class, void *data)
 {
     BusClass *bc = BUS_CLASS(class);
+    ResettableClass *rc = RESETTABLE_CLASS(class);
 
     class->unparent = bus_unparent;
     bc->get_fw_dev_path = default_bus_get_fw_dev_path;
+
+    rc->phases.init = bus_reset_init_phase;
+    rc->get_count = bus_get_reset_count;
+    rc->increment_count = bus_increment_reset_count;
+    rc->decrement_count = bus_decrement_reset_count;
+    rc->foreach_child = bus_foreach_reset_child;
 }
 
 static void qbus_finalize(Object *obj)
@@ -225,6 +281,10 @@ static const TypeInfo bus_info = {
     .instance_init = qbus_initfn,
     .instance_finalize = qbus_finalize,
     .class_init = bus_class_init,
+    .interfaces = (InterfaceInfo[]) {
+        { TYPE_RESETTABLE },
+        { }
+    },
 };
 
 static void bus_register_types(void)
diff --git a/hw/core/qdev.c b/hw/core/qdev.c
index 90037ba70c..8c3911c2bd 100644
--- a/hw/core/qdev.c
+++ b/hw/core/qdev.c
@@ -254,25 +254,56 @@ HotplugHandler *qdev_get_hotplug_handler(DeviceState *dev)
     return hotplug_ctrl;
 }
 
-static int qdev_reset_one(DeviceState *dev, void *opaque)
+void device_reset(DeviceState *dev, bool cold)
 {
-    device_reset(dev);
+    resettable_reset(OBJECT(dev), cold);
+}
 
-    return 0;
+bool device_is_resetting(DeviceState *dev)
+{
+    return (dev->resetting != 0);
+}
+
+static uint32_t device_get_reset_count(Object *obj)
+{
+    DeviceState *dev = DEVICE(obj);
+    return dev->resetting;
 }
 
-static int qbus_reset_one(BusState *bus, void *opaque)
+static uint32_t device_increment_reset_count(Object *obj)
 {
-    BusClass *bc = BUS_GET_CLASS(bus);
-    if (bc->reset) {
-        bc->reset(bus);
+    DeviceState *dev = DEVICE(obj);
+    return ++dev->resetting;
+}
+
+static uint32_t device_decrement_reset_count(Object *obj)
+{
+    DeviceState *dev = DEVICE(obj);
+    return --dev->resetting;
+}
+
+static void device_foreach_reset_child(Object *obj, void (*func)(Object *))
+{
+    DeviceState *dev = DEVICE(obj);
+    BusState *bus;
+    QLIST_FOREACH(bus, &dev->child_bus, sibling) {
+        func(OBJECT(bus));
+    }
+}
+
+static void device_reset_init_phase(Object *obj, bool cold)
+{
+    DeviceState *dev = DEVICE(obj);
+    DeviceClass *dc = DEVICE_GET_CLASS(dev);
+
+    if (dc->reset) {
+        dc->reset(dev);
     }
-    return 0;
 }
 
 void qdev_reset_all(DeviceState *dev)
 {
-    qdev_walk_children(dev, NULL, NULL, qdev_reset_one, qbus_reset_one, NULL);
+    device_reset(dev, false);
 }
 
 void qdev_reset_all_fn(void *opaque)
@@ -282,7 +313,7 @@ void qdev_reset_all_fn(void *opaque)
 
 void qbus_reset_all(BusState *bus)
 {
-    qbus_walk_children(bus, NULL, NULL, qdev_reset_one, qbus_reset_one, NULL);
+    bus_reset(bus, false);
 }
 
 void qbus_reset_all_fn(void *opaque)
@@ -864,7 +895,7 @@ static void device_set_realized(Object *obj, bool value, 
Error **errp)
             }
         }
         if (dev->hotplugged) {
-            device_reset(dev);
+            device_reset(dev, true);
         }
         dev->pending_deleted_event = false;
 
@@ -954,6 +985,7 @@ static void device_initfn(Object *obj)
 
     dev->instance_id_alias = -1;
     dev->realized = false;
+    dev->resetting = 0;
 
     object_property_add_bool(obj, "realized",
                              device_get_realized, device_set_realized, NULL);
@@ -1049,6 +1081,7 @@ static void device_unparent(Object *obj)
 static void device_class_init(ObjectClass *class, void *data)
 {
     DeviceClass *dc = DEVICE_CLASS(class);
+    ResettableClass *rc = RESETTABLE_CLASS(class);
 
     class->unparent = device_unparent;
 
@@ -1060,6 +1093,12 @@ static void device_class_init(ObjectClass *class, void 
*data)
      */
     dc->hotpluggable = true;
     dc->user_creatable = true;
+
+    rc->phases.init = device_reset_init_phase;
+    rc->get_count = device_get_reset_count;
+    rc->increment_count = device_increment_reset_count;
+    rc->decrement_count = device_decrement_reset_count;
+    rc->foreach_child = device_foreach_reset_child;
 }
 
 void device_class_set_parent_reset(DeviceClass *dc,
@@ -1117,6 +1156,10 @@ static const TypeInfo device_type_info = {
     .class_init = device_class_init,
     .abstract = true,
     .class_size = sizeof(DeviceClass),
+    .interfaces = (InterfaceInfo[]) {
+        { TYPE_RESETTABLE },
+        { }
+    },
 };
 
 static void qdev_register_types(void)
diff --git a/include/hw/qdev-core.h b/include/hw/qdev-core.h
index 537dd0054d..658a419350 100644
--- a/include/hw/qdev-core.h
+++ b/include/hw/qdev-core.h
@@ -6,6 +6,7 @@
 #include "qom/object.h"
 #include "hw/irq.h"
 #include "hw/hotplug.h"
+#include "hw/resettable.h"
 
 enum {
     DEV_NVECTORS_UNSPECIFIED = -1,
@@ -107,6 +108,11 @@ typedef struct DeviceClass {
     bool hotpluggable;
 
     /* callbacks */
+    /*
+     * Reset method here is deprecated and replaced by methods in the
+     * resettable class interface to implement a multi-phase reset.
+     * TODO: remove once every reset callback is unused
+     */
     DeviceReset reset;
     DeviceRealize realize;
     DeviceUnrealize unrealize;
@@ -131,6 +137,8 @@ struct NamedGPIOList {
 /**
  * DeviceState:
  * @realized: Indicates whether the device has been fully constructed.
+ * @resetting: Indicates whether the device is under reset. Also
+ * used to count how many times reset has been initiated on the device.
  *
  * This structure should not be accessed directly.  We declare it here
  * so that it can be embedded in individual device state structures.
@@ -152,6 +160,7 @@ struct DeviceState {
     int num_child_bus;
     int instance_id_alias;
     int alias_required_for_version;
+    uint32_t resetting;
 };
 
 struct DeviceListener {
@@ -198,6 +207,8 @@ typedef struct BusChild {
 /**
  * BusState:
  * @hotplug_handler: link to a hotplug handler associated with bus.
+ * @resetting: Indicates whether the device is under reset. Also
+ * used to count how many times reset has been initiated on the device.
  */
 struct BusState {
     Object obj;
@@ -209,6 +220,7 @@ struct BusState {
     int num_children;
     QTAILQ_HEAD(, BusChild) children;
     QLIST_ENTRY(BusState) sibling;
+    uint32_t resetting;
 };
 
 /**
@@ -375,11 +387,36 @@ int qdev_walk_children(DeviceState *dev,
                        qdev_walkerfn *post_devfn, qbus_walkerfn *post_busfn,
                        void *opaque);
 
-void qdev_reset_all(DeviceState *dev);
-void qdev_reset_all_fn(void *opaque);
+/**
+ * device_reset:
+ * Resets the device @dev, @cold tell whether to do a cold or warm reset.
+ * Uses the ressetable interface.
+ * Base behavior is to reset the device and its qdev/qbus subtree.
+ */
+void device_reset(DeviceState *dev, bool cold);
 
 /**
- * @qbus_reset_all:
+ * bus_reset:
+ * Resets the bus @bus, @cold tell whether to do a cold or warm reset.
+ * Uses the ressetable interface.
+ * Base behavior is to reset the bus and its qdev/qbus subtree.
+ */
+void bus_reset(BusState *bus, bool cold);
+
+/**
+ * device_is_resetting:
+ * Tell whether the device @dev is currently under reset.
+ */
+bool device_is_resetting(DeviceState *dev);
+
+/**
+ * bus_is_resetting:
+ * Tell whether the bus @bus is currently under reset.
+ */
+bool bus_is_resetting(BusState *bus);
+
+/**
+ * qbus/qdev_reset_all:
  * @bus: Bus to be reset.
  *
  * Reset @bus and perform a bus-level ("hard") reset of all devices connected
@@ -387,7 +424,13 @@ void qdev_reset_all_fn(void *opaque);
  * hard reset means that qbus_reset_all will reset all state of the device.
  * For PCI devices, for example, this will include the base address registers
  * or configuration space.
+ *
+ * Theses functions are deprecated, please use device/bus_reset or
+ * resettable_reset_* instead
+ * TODO: remove them when all occurence are removed
  */
+void qdev_reset_all(DeviceState *dev);
+void qdev_reset_all_fn(void *opaque);
 void qbus_reset_all(BusState *bus);
 void qbus_reset_all_fn(void *opaque);
 
@@ -409,17 +452,21 @@ void qdev_machine_init(void);
  * device_legacy_reset:
  *
  * Reset a single device (by calling the reset method).
+ *
+ * This function is deprecated, please use device_reset() instead.
+ * TODO: remove the function when all occurences are removed.
  */
 void device_legacy_reset(DeviceState *dev);
 
-static inline void device_reset(DeviceState *dev)
-{
-    device_legacy_reset(dev);
-}
-
+/**
+ * device_class_set_parent_reset:
+ * TODO: remove the function when DeviceClass's reset method
+ * is not used anymore.
+ */
 void device_class_set_parent_reset(DeviceClass *dc,
                                    DeviceReset dev_reset,
                                    DeviceReset *parent_reset);
+
 void device_class_set_parent_realize(DeviceClass *dc,
                                      DeviceRealize dev_realize,
                                      DeviceRealize *parent_realize);
diff --git a/tests/Makefile.include b/tests/Makefile.include
index 46a36c2c95..5b25905907 100644
--- a/tests/Makefile.include
+++ b/tests/Makefile.include
@@ -547,6 +547,7 @@ tests/fp/%:
 
 tests/test-qdev-global-props$(EXESUF): tests/test-qdev-global-props.o \
        hw/core/qdev.o hw/core/qdev-properties.o hw/core/hotplug.o\
+       hw/core/resettable.o \
        hw/core/bus.o \
        hw/core/irq.o \
        hw/core/fw-path-provider.o \
-- 
2.21.0