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 #include "qemu/log.h"
  20 #include "qemu/module.h"
  21
  22 static WatchdogTimerModel model = {
  23     .wdt_name = TYPE_WDT_DIAG288,
  24     .wdt_description = "diag288 device for s390x platform",
  25 };
  26
  27 static 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
  38 static void wdt_diag288_reset(DeviceState *dev)
  39 {
  40     DIAG288State *diag288 = DIAG288(dev);
  41
  42     diag288->enabled = false;
  43     timer_del(diag288->timer);
  44 }
  45
  46 static void diag288_reset(void *opaque)
  47 {
  48     DeviceState *diag288 = opaque;
  49
  50     wdt_diag288_reset(diag288);
  51 }
  52
  53 static 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
  71 static 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
 100 static 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
 109 static void wdt_diag288_unrealize(DeviceState *dev, Error **errp)
 110 {
 111     DIAG288State *diag288 = DIAG288(dev);
 112
 113     timer_del(diag288->timer);
 114     timer_free(diag288->timer);
 115 }
 116
 117 static void wdt_diag288_class_init(ObjectClass *klass, void *data)
 118 {
 119     DeviceClass *dc = DEVICE_CLASS(klass);
 120     DIAG288Class *diag288 = DIAG288_CLASS(klass);
 121
 122     dc->realize = wdt_diag288_realize;
 123     dc->unrealize = wdt_diag288_unrealize;
 124     dc->reset = wdt_diag288_reset;
 125     dc->hotpluggable = false;
 126     set_bit(DEVICE_CATEGORY_MISC, dc->categories);
 127     dc->vmsd = &vmstate_diag288;
 128     diag288->handle_timer = wdt_diag288_handle_timer;
 129 }
 130
 131 static 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
 139 static void wdt_diag288_register_types(void)
 140 {
 141     watchdog_add_model(&model);
 142     type_register_static(&wdt_diag288_info);
 143 }
 144
 145 type_init(wdt_diag288_register_types)