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
  21 static WatchdogTimerModel model = {
  22     .wdt_name = TYPE_WDT_DIAG288,
  23     .wdt_description = "diag288 device for s390x platform",
  24 };
  25
  26 static const VMStateDescription vmstate_diag288 = {
  27     .name = "vmstate_diag288",
  28     .version_id = 0,
  29     .minimum_version_id = 0,
  30     .fields = (VMStateField[]) {
  31         VMSTATE_TIMER_PTR(timer, DIAG288State),
  32         VMSTATE_BOOL(enabled, DIAG288State),
  33         VMSTATE_END_OF_LIST()
  34     }
  35 };
  36
  37 static void wdt_diag288_reset(DeviceState *dev)
  38 {
  39     DIAG288State *diag288 = DIAG288(dev);
  40
  41     diag288->enabled = false;
  42     timer_del(diag288->timer);
  43 }
  44
  45 static void diag288_reset(void *opaque)
  46 {
  47     DeviceState *diag288 = opaque;
  48
  49     wdt_diag288_reset(diag288);
  50 }
  51
  52 static void diag288_timer_expired(void *dev)
  53 {
  54     qemu_log_mask(CPU_LOG_RESET, "Watchdog timer expired.\n");
  55     /* Reset the watchdog only if the guest gets notified about
  56      * expiry. watchdog_perform_action() may temporarily relinquish
  57      * the BQL; reset before triggering the action to avoid races with
  58      * diag288 instructions. */
  59     switch (get_watchdog_action()) {
  60     case WATCHDOG_ACTION_DEBUG:
  61     case WATCHDOG_ACTION_NONE:
  62     case WATCHDOG_ACTION_PAUSE:
  63         break;
  64     default:
  65         wdt_diag288_reset(dev);
  66     }
  67     watchdog_perform_action();
  68 }
  69
  70 static int wdt_diag288_handle_timer(DIAG288State *diag288,
  71                                      uint64_t func, uint64_t timeout)
  72 {
  73     switch (func) {
  74     case WDT_DIAG288_INIT:
  75         diag288->enabled = true;
  76         /* fall through */
  77     case WDT_DIAG288_CHANGE:
  78         if (!diag288->enabled) {
  79             return -1;
  80         }
  81         timer_mod(diag288->timer,
  82                   qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) +
  83                   timeout * NANOSECONDS_PER_SECOND);
  84         break;
  85     case WDT_DIAG288_CANCEL:
  86         if (!diag288->enabled) {
  87             return -1;
  88         }
  89         diag288->enabled = false;
  90         timer_del(diag288->timer);
  91         break;
  92     default:
  93         return -1;
  94     }
  95
  96     return 0;
  97 }
  98
  99 static void wdt_diag288_realize(DeviceState *dev, Error **errp)
 100 {
 101     DIAG288State *diag288 = DIAG288(dev);
 102
 103     qemu_register_reset(diag288_reset, diag288);
 104     diag288->timer = timer_new_ns(QEMU_CLOCK_VIRTUAL, diag288_timer_expired,
 105                                   dev);
 106 }
 107
 108 static void wdt_diag288_unrealize(DeviceState *dev, Error **errp)
 109 {
 110     DIAG288State *diag288 = DIAG288(dev);
 111
 112     timer_del(diag288->timer);
 113     timer_free(diag288->timer);
 114 }
 115
 116 static 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_MISC, dc->categories);
 126     dc->vmsd = &vmstate_diag288;
 127     diag288->handle_timer = wdt_diag288_handle_timer;
 128 }
 129
 130 static const TypeInfo wdt_diag288_info = {
 131     .class_init = wdt_diag288_class_init,
 132     .parent = TYPE_DEVICE,
 133     .name  = TYPE_WDT_DIAG288,
 134     .instance_size  = sizeof(DIAG288State),
 135     .class_size = sizeof(DIAG288Class),
 136 };
 137
 138 static void wdt_diag288_register_types(void)
 139 {
 140     watchdog_add_model(&model);
 141     type_register_static(&wdt_diag288_info);
 142 }
 143
 144 type_init(wdt_diag288_register_types)