LXR qemu/hw/core/vm-change-state-handler.c

   1/*
   2 *  qdev vm change state handlers
   3 *
   4 *  This program is free software; you can redistribute it and/or modify
   5 *  it under the terms of the GNU General Public License as published by
   6 *  the Free Software Foundation; either version 2 of the License,
   7 *  or (at your option) any later version.
   8 *
   9 *  This program is distributed in the hope that it will be useful,
  10 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 *  GNU General Public License for more details.
  13 *
  14 *  You should have received a copy of the GNU General Public License
  15 *  along with this program; if not, see <http://www.gnu.org/licenses/>.
  16 */
  17
  18#include "qemu/osdep.h"
  19#include "hw/qdev-core.h"
  20#include "sysemu/runstate.h"
  21
  22static int qdev_get_dev_tree_depth(DeviceState *dev)
  23{
  24    int depth;
  25
  26    for (depth = 0; dev; depth++) {
  27        BusState *bus = dev->parent_bus;
  28
  29        if (!bus) {
  30            break;
  31        }
  32
  33        dev = bus->parent;
  34    }
  35
  36    return depth;
  37}
  38
  39/**
  40 * qdev_add_vm_change_state_handler:
  41 * @dev: the device that owns this handler
  42 * @cb: the callback function to be invoked
  43 * @opaque: user data passed to the callback function
  44 *
  45 * This function works like qemu_add_vm_change_state_handler() except callbacks
  46 * are invoked in qdev tree depth order.  Ordering is desirable when callbacks
  47 * of children depend on their parent's callback having completed first.
  48 *
  49 * For example, when qdev_add_vm_change_state_handler() is used, a host
  50 * controller's callback is invoked before the children on its bus when the VM
  51 * starts running.  The order is reversed when the VM stops running.
  52 *
  53 * Returns: an entry to be freed with qemu_del_vm_change_state_handler()
  54 */
  55VMChangeStateEntry *qdev_add_vm_change_state_handler(DeviceState *dev,
  56                                                     VMChangeStateHandler *cb,
  57                                                     void *opaque)
  58{
  59    int depth = qdev_get_dev_tree_depth(dev);
  60
  61    return qemu_add_vm_change_state_handler_prio(cb, opaque, depth);
  62}
  63