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 /* This is the timer.  We use a global here because the watchdog
  39  * code ensures there is only one watchdog (it is located at a fixed,
  40  * unchangable IO port, so there could only ever be one anyway).
  41  */
  42 static QEMUTimer *timer = NULL;
  43
  44 /* A write to this register enables the timer. */
  45 static void ib700_write_enable_reg(void *vp, uint32_t addr, uint32_t data)
  46 {
  47     static int time_map[] = {
  48         30, 28, 26, 24, 22, 20, 18, 16,
  49         14, 12, 10,  8,  6,  4,  2,  0
  50     };
  51     int64 timeout;
  52
  53     ib700_debug("addr = %x, data = %x\n", addr, data);
  54
  55     timeout = (int64_t) time_map[data & 0xF] * get_ticks_per_sec();
  56     qemu_mod_timer(timer, qemu_get_clock (vm_clock) + timeout);
  57 }
  58
  59 /* A write (of any value) to this register disables the timer. */
  60 static void ib700_write_disable_reg(void *vp, uint32_t addr, uint32_t data)
  61 {
  62     ib700_debug("addr = %x, data = %x\n", addr, data);
  63
  64     qemu_del_timer(timer);
  65 }
  66
  67 /* This is called when the watchdog expires. */
  68 static void ib700_timer_expired(void *vp)
  69 {
  70     ib700_debug("watchdog expired\n");
  71
  72     watchdog_perform_action();
  73     qemu_del_timer(timer);
  74 }
  75
  76 static void ib700_save(QEMUFile *f, void *vp)
  77 {
  78     qemu_put_timer(f, timer);
  79 }
  80
  81 static int ib700_load(QEMUFile *f, void *vp, int version)
  82 {
  83     if (version != 0)
  84         return -EINVAL;
  85
  86     qemu_get_timer(f, timer);
  87
  88     return 0;
  89 }
  90
  91 static int wdt_ib700_init(ISADevice *dev)
  92 {
  93     timer = qemu_new_timer(vm_clock, ib700_timer_expired, NULL);
  94     register_savevm("ib700_wdt", -1, 0, ib700_save, ib700_load, NULL);
  95     register_ioport_write(0x441, 2, 1, ib700_write_disable_reg, NULL);
  96     register_ioport_write(0x443, 2, 1, ib700_write_enable_reg, NULL);
  97
  98     return 0;
  99 }
 100
 101 static WatchdogTimerModel model = {
 102     .wdt_name = "ib700",
 103     .wdt_description = "iBASE 700",
 104 };
 105
 106 static ISADeviceInfo wdt_ib700_info = {
 107     .qdev.name = "ib700",
 108     .qdev.size = sizeof(ISADevice),
 109     .init      = wdt_ib700_init,
 110 };
 111
 112 static void wdt_ib700_register_devices(void)
 113 {
 114     watchdog_add_model(&model);
 115     isa_qdev_register(&wdt_ib700_info);
 116 }
 117
 118 device_init(wdt_ib700_register_devices);