LXR qemu/hw/watchdog/wdt

   1/*
   2 * watchdog device diag288 support
   3 *
   4 * Copyright IBM, Corp. 2015
   5 *
   6 * Authors:
   7 *  Xu Wang <gesaint@linux.vnet.ibm.com>
   8 *
   9 * This work is licensed under the terms of the GNU GPL, version 2 or (at your
  10 * option) any later version.  See the COPYING file in the top-level directory.
  11 *
  12 */
  13
  14#include "qemu/osdep.h"
  15#include "sysemu/reset.h"
  16#include "sysemu/watchdog.h"
  17#include "qemu/timer.h"
  18#include "hw/watchdog/wdt_diag288.h"
  19#include "migration/vmstate.h"
  20#include "qemu/log.h"
  21
  22static WatchdogTimerModel model = {
  23    .wdt_name = TYPE_WDT_DIAG288,
  24    .wdt_description = "diag288 device for s390x platform",
  25};
  26
  27static const VMStateDescription vmstate_diag288 = {
  28    .name = "vmstate_diag288",
  29    .version_id = 0,
  30    .minimum_version_id = 0,
  31    .fields = (VMStateField[]) {
  32        VMSTATE_TIMER_PTR(timer, DIAG288State),
  33        VMSTATE_BOOL(enabled, DIAG288State),
  34        VMSTATE_END_OF_LIST()
  35    }
  36};
  37
  38static void wdt_diag288_reset(DeviceState *dev)
  39{
  40    DIAG288State *diag288 = DIAG288(dev);
  41
  42    diag288->enabled = false;
  43    timer_del(diag288->timer);
  44}
  45
  46static void diag288_reset(void *opaque)
  47{
  48    DeviceState *diag288 = opaque;
  49
  50    wdt_diag288_reset(diag288);
  51}
  52
  53static void diag288_timer_expired(void *dev)
  54{
  55    qemu_log_mask(CPU_LOG_RESET, "Watchdog timer expired.\n");
  56    /* Reset the watchdog only if the guest gets notified about
  57     * expiry. watchdog_perform_action() may temporarily relinquish
  58     * the BQL; reset before triggering the action to avoid races with
  59     * diag288 instructions. */
  60    switch (get_watchdog_action()) {
  61    case WATCHDOG_ACTION_DEBUG:
  62    case WATCHDOG_ACTION_NONE:
  63    case WATCHDOG_ACTION_PAUSE:
  64        break;
  65    default:
  66        wdt_diag288_reset(dev);
  67    }
  68    watchdog_perform_action();
  69}
  70
  71static int wdt_diag288_handle_timer(DIAG288State *diag288,
  72                                     uint64_t func, uint64_t timeout)
  73{
  74    switch (func) {
  75    case WDT_DIAG288_INIT:
  76        diag288->enabled = true;
  77        /* fall through */
  78    case WDT_DIAG288_CHANGE:
  79        if (!diag288->enabled) {
  80            return -1;
  81        }
  82        timer_mod(diag288->timer,
  83                  qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) +
  84                  timeout * NANOSECONDS_PER_SECOND);
  85        break;
  86    case WDT_DIAG288_CANCEL:
  87        if (!diag288->enabled) {
  88            return -1;
  89        }
  90        diag288->enabled = false;
  91        timer_del(diag288->timer);
  92        break;
  93    default:
  94        return -1;
  95    }
  96
  97    return 0;
  98}
  99
 100static void wdt_diag288_realize(DeviceState *dev, Error **errp)
 101{
 102    DIAG288State *diag288 = DIAG288(dev);
 103
 104    qemu_register_reset(diag288_reset, diag288);
 105    diag288->timer = timer_new_ns(QEMU_CLOCK_VIRTUAL, diag288_timer_expired,
 106                                  dev);
 107}
 108
 109static void wdt_diag288_unrealize(DeviceState *dev)
 110{
 111    DIAG288State *diag288 = DIAG288(dev);
 112
 113    timer_free(diag288->timer);
 114}
 115
 116static void wdt_diag288_class_init(ObjectClass *klass, void *data)
 117{
 118    DeviceClass *dc = DEVICE_CLASS(klass);
 119    DIAG288Class *diag288 = DIAG288_CLASS(klass);
 120
 121    dc->realize = wdt_diag288_realize;
 122    dc->unrealize = wdt_diag288_unrealize;
 123    dc->reset = wdt_diag288_reset;
 124    dc->hotpluggable = false;
 125    set_bit(DEVICE_CATEGORY_WATCHDOG, dc->categories);
 126    dc->vmsd = &vmstate_diag288;
 127    diag288->handle_timer = wdt_diag288_handle_timer;
 128    dc->desc = "diag288 device for s390x platform";
 129}
 130
 131static const TypeInfo wdt_diag288_info = {
 132    .class_init = wdt_diag288_class_init,
 133    .parent = TYPE_DEVICE,
 134    .name  = TYPE_WDT_DIAG288,
 135    .instance_size  = sizeof(DIAG288State),
 136    .class_size = sizeof(DIAG288Class),
 137};
 138
 139static void wdt_diag288_register_types(void)
 140{
 141    watchdog_add_model(&model);
 142    type_register_static(&wdt_diag288_info);
 143}
 144
 145type_init(wdt_diag288_register_types)
 146