hw/watchdog/wdt_diag288.c

   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/watchdog.h"
  16 #include "hw/sysbus.h"
  17 #include "qemu/timer.h"
  18 #include "hw/watchdog/wdt_diag288.h"
  19
  20 static WatchdogTimerModel model = {
  21     .wdt_name = TYPE_WDT_DIAG288,
  22     .wdt_description = "diag288 device for s390x platform",
  23 };
  24
  25 static const VMStateDescription vmstate_diag288 = {
  26     .name = "vmstate_diag288",
  27     .version_id = 0,
  28     .minimum_version_id = 0,
  29     .fields = (VMStateField[]) {
  30         VMSTATE_TIMER_PTR(timer, DIAG288State),
  31         VMSTATE_BOOL(enabled, DIAG288State),
  32         VMSTATE_END_OF_LIST()
  33     }
  34 };
  35
  36 static void wdt_diag288_reset(DeviceState *dev)
  37 {
  38     DIAG288State *diag288 = DIAG288(dev);
  39
  40     diag288->enabled = false;
  41     timer_del(diag288->timer);
  42 }
  43
  44 static void diag288_reset(void *opaque)
  45 {
  46     DeviceState *diag288 = opaque;
  47
  48     wdt_diag288_reset(diag288);
  49 }
  50
  51 static void diag288_timer_expired(void *dev)
  52 {
  53     qemu_log_mask(CPU_LOG_RESET, "Watchdog timer expired.\n");
  54     /* Reset the watchdog only if the guest gets notified about
  55      * expiry. watchdog_perform_action() may temporarily relinquish
  56      * the BQL; reset before triggering the action to avoid races with
  57      * diag288 instructions. */
  58     switch (get_watchdog_action()) {
  59     case WDT_DEBUG:
  60     case WDT_NONE:
  61     case WDT_PAUSE:
  62         break;
  63     default:
  64         wdt_diag288_reset(dev);
  65     }
  66     watchdog_perform_action();
  67 }
  68
  69 static int wdt_diag288_handle_timer(DIAG288State *diag288,
  70                                      uint64_t func, uint64_t timeout)
  71 {
  72     switch (func) {
  73     case WDT_DIAG288_INIT:
  74         diag288->enabled = true;
  75         /* fall through */
  76     case WDT_DIAG288_CHANGE:
  77         if (!diag288->enabled) {
  78             return -1;
  79         }
  80         timer_mod(diag288->timer,
  81                   qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) +
  82                   timeout * NANOSECONDS_PER_SECOND);
  83         break;
  84     case WDT_DIAG288_CANCEL:
  85         if (!diag288->enabled) {
  86             return -1;
  87         }
  88         diag288->enabled = false;
  89         timer_del(diag288->timer);
  90         break;
  91     default:
  92         return -1;
  93     }
  94
  95     return 0;
  96 }
  97
  98 static void wdt_diag288_realize(DeviceState *dev, Error **errp)
  99 {
 100     DIAG288State *diag288 = DIAG288(dev);
 101
 102     qemu_register_reset(diag288_reset, diag288);
 103     diag288->timer = timer_new_ns(QEMU_CLOCK_VIRTUAL, diag288_timer_expired,
 104                                   dev);
 105 }
 106
 107 static void wdt_diag288_unrealize(DeviceState *dev, Error **errp)
 108 {
 109     DIAG288State *diag288 = DIAG288(dev);
 110
 111     timer_del(diag288->timer);
 112     timer_free(diag288->timer);
 113 }
 114
 115 static void wdt_diag288_class_init(ObjectClass *klass, void *data)
 116 {
 117     DeviceClass *dc = DEVICE_CLASS(klass);
 118     DIAG288Class *diag288 = DIAG288_CLASS(klass);
 119
 120     dc->realize = wdt_diag288_realize;
 121     dc->unrealize = wdt_diag288_unrealize;
 122     dc->reset = wdt_diag288_reset;
 123     set_bit(DEVICE_CATEGORY_MISC, dc->categories);
 124     dc->vmsd = &vmstate_diag288;
 125     diag288->handle_timer = wdt_diag288_handle_timer;
 126 }
 127
 128 static const TypeInfo wdt_diag288_info = {
 129     .class_init = wdt_diag288_class_init,
 130     .parent = TYPE_DEVICE,
 131     .name  = TYPE_WDT_DIAG288,
 132     .instance_size  = sizeof(DIAG288State),
 133     .class_size = sizeof(DIAG288Class),
 134 };
 135
 136 static void wdt_diag288_register_types(void)
 137 {
 138     watchdog_add_model(&model);
 139     type_register_static(&wdt_diag288_info);
 140 }
 141
 142 type_init(wdt_diag288_register_types)