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, write to the Free Software
  18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301,
  19  * USA.
  20  *
  21  * By Richard W.M. Jones (rjones@redhat.com).
  22  */
  23
  24 #include "qemu-common.h"
  25 #include "qemu-timer.h"
  26 #include "watchdog.h"
  27 #include "hw.h"
  28 #include "isa.h"
  29 #include "pc.h"
  30
  31 /*#define IB700_DEBUG 1*/
  32
  33 #ifdef IB700_DEBUG
  34 #define ib700_debug(fs,...)                                     \
  35     fprintf(stderr,"ib700: %s: "fs,__func__,##__VA_ARGS__)
  36 #else
  37 #define ib700_debug(fs,...)
  38 #endif
  39
  40 /* This is the timer.  We use a global here because the watchdog
  41  * code ensures there is only one watchdog (it is located at a fixed,
  42  * unchangable IO port, so there could only ever be one anyway).
  43  */
  44 static QEMUTimer *timer = NULL;
  45
  46 /* A write to this register enables the timer. */
  47 static void ib700_write_enable_reg(void *vp, uint32_t addr, uint32_t data)
  48 {
  49     static int time_map[] = {
  50         30, 28, 26, 24, 22, 20, 18, 16,
  51         14, 12, 10,  8,  6,  4,  2,  0
  52     };
  53     int64 timeout;
  54
  55     ib700_debug("addr = %x, data = %x\n", addr, data);
  56
  57     timeout = (int64_t) time_map[data & 0xF] * ticks_per_sec;
  58     qemu_mod_timer(timer, qemu_get_clock (vm_clock) + timeout);
  59 }
  60
  61 /* A write (of any value) to this register disables the timer. */
  62 static void ib700_write_disable_reg(void *vp, uint32_t addr, uint32_t data)
  63 {
  64     ib700_debug("addr = %x, data = %x\n", addr, data);
  65
  66     qemu_del_timer(timer);
  67 }
  68
  69 /* This is called when the watchdog expires. */
  70 static void ib700_timer_expired(void *vp)
  71 {
  72     ib700_debug("watchdog expired\n");
  73
  74     watchdog_perform_action();
  75     qemu_del_timer(timer);
  76 }
  77
  78 static void ib700_save(QEMUFile *f, void *vp)
  79 {
  80     qemu_put_timer(f, timer);
  81 }
  82
  83 static int ib700_load(QEMUFile *f, void *vp, int version)
  84 {
  85     if (version != 0)
  86         return -EINVAL;
  87
  88     qemu_get_timer(f, timer);
  89
  90     return 0;
  91 }
  92
  93 /* Create and initialize a virtual IB700 during PC creation. */
  94 static void ib700_pc_init(PCIBus *unused)
  95 {
  96     register_savevm("ib700_wdt", -1, 0, ib700_save, ib700_load, NULL);
  97
  98     register_ioport_write(0x441, 2, 1, ib700_write_disable_reg, NULL);
  99     register_ioport_write(0x443, 2, 1, ib700_write_enable_reg, NULL);
 100 }
 101
 102 static WatchdogTimerModel model = {
 103     .wdt_name = "ib700",
 104     .wdt_description = "iBASE 700",
 105     .wdt_pc_init = ib700_pc_init,
 106 };
 107
 108 void wdt_ib700_init(void)
 109 {
 110     watchdog_add_model(&model);
 111     timer = qemu_new_timer(vm_clock, ib700_timer_expired, NULL);
 112 }