hw/wdt_ib700.c

   1 /*
   2  * Virtual hardware watchdog.
   3  *
   4  * Copyright (C) 2009 Red Hat Inc.
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License
   8  * as published by the Free Software Foundation; either version 2
   9  * of the License, or (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, see <http://www.gnu.org/licenses/>.
  18  *
  19  * By Richard W.M. Jones (rjones@redhat.com).
  20  */
  21
  22 #include "qemu-common.h"
  23 #include "qemu-timer.h"
  24 #include "watchdog.h"
  25 #include "hw.h"
  26 #include "isa.h"
  27 #include "pc.h"
  28
  29 /*#define IB700_DEBUG 1*/
  30
  31 #ifdef IB700_DEBUG
  32 #define ib700_debug(fs,...)                                     \
  33     fprintf(stderr,"ib700: %s: "fs,__func__,##__VA_ARGS__)
  34 #else
  35 #define ib700_debug(fs,...)
  36 #endif
  37
  38 typedef struct IB700state {
  39     ISADevice dev;
  40     QEMUTimer *timer;
  41 } IB700State;
  42
  43 /* This is the timer.  We use a global here because the watchdog
  44  * code ensures there is only one watchdog (it is located at a fixed,
  45  * unchangeable IO port, so there could only ever be one anyway).
  46  */
  47
  48 /* A write to this register enables the timer. */
  49 static void ib700_write_enable_reg(void *vp, uint32_t addr, uint32_t data)
  50 {
  51     IB700State *s = vp;
  52     static int time_map[] = {
  53         30, 28, 26, 24, 22, 20, 18, 16,
  54         14, 12, 10,  8,  6,  4,  2,  0
  55     };
  56     int64_t timeout;
  57
  58     ib700_debug("addr = %x, data = %x\n", addr, data);
  59
  60     timeout = (int64_t) time_map[data & 0xF] * get_ticks_per_sec();
  61     qemu_mod_timer(s->timer, qemu_get_clock_ns (vm_clock) + timeout);
  62 }
  63
  64 /* A write (of any value) to this register disables the timer. */
  65 static void ib700_write_disable_reg(void *vp, uint32_t addr, uint32_t data)
  66 {
  67     IB700State *s = vp;
  68
  69     ib700_debug("addr = %x, data = %x\n", addr, data);
  70
  71     qemu_del_timer(s->timer);
  72 }
  73
  74 /* This is called when the watchdog expires. */
  75 static void ib700_timer_expired(void *vp)
  76 {
  77     IB700State *s = vp;
  78
  79     ib700_debug("watchdog expired\n");
  80
  81     watchdog_perform_action();
  82     qemu_del_timer(s->timer);
  83 }
  84
  85 static const VMStateDescription vmstate_ib700 = {
  86     .name = "ib700_wdt",
  87     .version_id = 0,
  88     .minimum_version_id = 0,
  89     .minimum_version_id_old = 0,
  90     .fields      = (VMStateField []) {
  91         VMSTATE_TIMER(timer, IB700State),
  92         VMSTATE_END_OF_LIST()
  93     }
  94 };
  95
  96 static int wdt_ib700_init(ISADevice *dev)
  97 {
  98     IB700State *s = DO_UPCAST(IB700State, dev, dev);
  99
 100     ib700_debug("watchdog init\n");
 101
 102     s->timer = qemu_new_timer_ns(vm_clock, ib700_timer_expired, s);
 103     register_ioport_write(0x441, 2, 1, ib700_write_disable_reg, s);
 104     register_ioport_write(0x443, 2, 1, ib700_write_enable_reg, s);
 105
 106     return 0;
 107 }
 108
 109 static void wdt_ib700_reset(DeviceState *dev)
 110 {
 111     IB700State *s = DO_UPCAST(IB700State, dev.qdev, dev);
 112
 113     ib700_debug("watchdog reset\n");
 114
 115     qemu_del_timer(s->timer);
 116 }
 117
 118 static WatchdogTimerModel model = {
 119     .wdt_name = "ib700",
 120     .wdt_description = "iBASE 700",
 121 };
 122
 123 static ISADeviceInfo wdt_ib700_info = {
 124     .qdev.name  = "ib700",
 125     .qdev.size  = sizeof(IB700State),
 126     .qdev.vmsd  = &vmstate_ib700,
 127     .qdev.reset = wdt_ib700_reset,
 128     .init       = wdt_ib700_init,
 129 };
 130
 131 static void wdt_ib700_register_devices(void)
 132 {
 133     watchdog_add_model(&model);
 134     isa_qdev_register(&wdt_ib700_info);
 135 }
 136
 137 device_init(wdt_ib700_register_devices);