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