qemu/hw/core/bus.c
Peter Maydell be1ba4d56e hw/core/bus.c: Only the main system bus can have no parent
In commit 80376c3fc2 in 2010 we added a workaround for
some qbus buses not being connected to qdev devices -- if the
bus has no parent object then we register a reset function which
resets the bus on system reset (and unregister it when the
bus is unparented).

Nearly a decade later, we have now no buses in the tree which
are created with non-NULL parents, so we can remove the
workaround and instead just assert that if the bus has a NULL
parent then it is the main system bus.

(The absence of other parentless buses was confirmed by
code inspection of all the callsites of qbus_create() and
qbus_create_inplace() and cross-checked by 'make check'.)

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Damien Hedde <damien.hedde@greensocs.com>
Tested-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-id: 20190523150543.22676-1-peter.maydell@linaro.org
2019-06-13 15:14:03 +01:00

234 lines
6.3 KiB
C

/*
* Dynamic device configuration and creation -- buses.
*
* Copyright (c) 2009 CodeSourcery
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, see <http://www.gnu.org/licenses/>.
*/
#include "qemu/osdep.h"
#include "qemu/ctype.h"
#include "qemu/module.h"
#include "hw/qdev.h"
#include "qapi/error.h"
void qbus_set_hotplug_handler(BusState *bus, Object *handler, Error **errp)
{
object_property_set_link(OBJECT(bus), OBJECT(handler),
QDEV_HOTPLUG_HANDLER_PROPERTY, errp);
}
void qbus_set_bus_hotplug_handler(BusState *bus, Error **errp)
{
qbus_set_hotplug_handler(bus, OBJECT(bus), errp);
}
int qbus_walk_children(BusState *bus,
qdev_walkerfn *pre_devfn, qbus_walkerfn *pre_busfn,
qdev_walkerfn *post_devfn, qbus_walkerfn *post_busfn,
void *opaque)
{
BusChild *kid;
int err;
if (pre_busfn) {
err = pre_busfn(bus, opaque);
if (err) {
return err;
}
}
QTAILQ_FOREACH(kid, &bus->children, sibling) {
err = qdev_walk_children(kid->child,
pre_devfn, pre_busfn,
post_devfn, post_busfn, opaque);
if (err < 0) {
return err;
}
}
if (post_busfn) {
err = post_busfn(bus, opaque);
if (err) {
return err;
}
}
return 0;
}
static void qbus_realize(BusState *bus, DeviceState *parent, const char *name)
{
const char *typename = object_get_typename(OBJECT(bus));
BusClass *bc;
int i, bus_id;
bus->parent = parent;
if (name) {
bus->name = g_strdup(name);
} else if (bus->parent && bus->parent->id) {
/* parent device has id -> use it plus parent-bus-id for bus name */
bus_id = bus->parent->num_child_bus;
bus->name = g_strdup_printf("%s.%d", bus->parent->id, bus_id);
} else {
/* no id -> use lowercase bus type plus global bus-id for bus name */
bc = BUS_GET_CLASS(bus);
bus_id = bc->automatic_ids++;
bus->name = g_strdup_printf("%s.%d", typename, bus_id);
for (i = 0; bus->name[i]; i++) {
bus->name[i] = qemu_tolower(bus->name[i]);
}
}
if (bus->parent) {
QLIST_INSERT_HEAD(&bus->parent->child_bus, bus, sibling);
bus->parent->num_child_bus++;
object_property_add_child(OBJECT(bus->parent), bus->name, OBJECT(bus), NULL);
object_unref(OBJECT(bus));
} else {
/* The only bus without a parent is the main system bus */
assert(bus == sysbus_get_default());
}
}
static void bus_unparent(Object *obj)
{
BusState *bus = BUS(obj);
BusChild *kid;
/* Only the main system bus has no parent, and that bus is never freed */
assert(bus->parent);
while ((kid = QTAILQ_FIRST(&bus->children)) != NULL) {
DeviceState *dev = kid->child;
object_unparent(OBJECT(dev));
}
QLIST_REMOVE(bus, sibling);
bus->parent->num_child_bus--;
bus->parent = NULL;
}
void qbus_create_inplace(void *bus, size_t size, const char *typename,
DeviceState *parent, const char *name)
{
object_initialize(bus, size, typename);
qbus_realize(bus, parent, name);
}
BusState *qbus_create(const char *typename, DeviceState *parent, const char *name)
{
BusState *bus;
bus = BUS(object_new(typename));
qbus_realize(bus, parent, name);
return bus;
}
static bool bus_get_realized(Object *obj, Error **errp)
{
BusState *bus = BUS(obj);
return bus->realized;
}
static void bus_set_realized(Object *obj, bool value, Error **errp)
{
BusState *bus = BUS(obj);
BusClass *bc = BUS_GET_CLASS(bus);
BusChild *kid;
Error *local_err = NULL;
if (value && !bus->realized) {
if (bc->realize) {
bc->realize(bus, &local_err);
}
/* TODO: recursive realization */
} else if (!value && bus->realized) {
QTAILQ_FOREACH(kid, &bus->children, sibling) {
DeviceState *dev = kid->child;
object_property_set_bool(OBJECT(dev), false, "realized",
&local_err);
if (local_err != NULL) {
break;
}
}
if (bc->unrealize && local_err == NULL) {
bc->unrealize(bus, &local_err);
}
}
if (local_err != NULL) {
error_propagate(errp, local_err);
return;
}
bus->realized = value;
}
static void qbus_initfn(Object *obj)
{
BusState *bus = BUS(obj);
QTAILQ_INIT(&bus->children);
object_property_add_link(obj, QDEV_HOTPLUG_HANDLER_PROPERTY,
TYPE_HOTPLUG_HANDLER,
(Object **)&bus->hotplug_handler,
object_property_allow_set_link,
0,
NULL);
object_property_add_bool(obj, "realized",
bus_get_realized, bus_set_realized, NULL);
}
static char *default_bus_get_fw_dev_path(DeviceState *dev)
{
return g_strdup(object_get_typename(OBJECT(dev)));
}
static void bus_class_init(ObjectClass *class, void *data)
{
BusClass *bc = BUS_CLASS(class);
class->unparent = bus_unparent;
bc->get_fw_dev_path = default_bus_get_fw_dev_path;
}
static void qbus_finalize(Object *obj)
{
BusState *bus = BUS(obj);
g_free(bus->name);
}
static const TypeInfo bus_info = {
.name = TYPE_BUS,
.parent = TYPE_OBJECT,
.instance_size = sizeof(BusState),
.abstract = true,
.class_size = sizeof(BusClass),
.instance_init = qbus_initfn,
.instance_finalize = qbus_finalize,
.class_init = bus_class_init,
};
static void bus_register_types(void)
{
type_register_static(&bus_info);
}
type_init(bus_register_types)