hw/mc146818rtc.c

   1 /*
   2  * QEMU MC146818 RTC emulation
   3  *
   4  * Copyright (c) 2003-2004 Fabrice Bellard
   5  *
   6  * Permission is hereby granted, free of charge, to any person obtaining a copy
   7  * of this software and associated documentation files (the "Software"), to deal
   8  * in the Software without restriction, including without limitation the rights
   9  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  10  * copies of the Software, and to permit persons to whom the Software is
  11  * furnished to do so, subject to the following conditions:
  12  *
  13  * The above copyright notice and this permission notice shall be included in
  14  * all copies or substantial portions of the Software.
  15  *
  16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  17  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  19  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  20  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  21  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  22  * THE SOFTWARE.
  23  */
  24 #include "hw.h"
  25 #include "qemu-timer.h"
  26 #include "sysemu.h"
  27 #include "mc146818rtc.h"
  28
  29 #ifdef TARGET_I386
  30 #include "apic.h"
  31 #endif
  32
  33 //#define DEBUG_CMOS
  34 //#define DEBUG_COALESCED
  35
  36 #ifdef DEBUG_CMOS
  37 # define CMOS_DPRINTF(format, ...)      printf(format, ## __VA_ARGS__)
  38 #else
  39 # define CMOS_DPRINTF(format, ...)      do { } while (0)
  40 #endif
  41
  42 #ifdef DEBUG_COALESCED
  43 # define DPRINTF_C(format, ...)      printf(format, ## __VA_ARGS__)
  44 #else
  45 # define DPRINTF_C(format, ...)      do { } while (0)
  46 #endif
  47
  48 #define RTC_REINJECT_ON_ACK_COUNT 20
  49
  50 typedef struct RTCState {
  51     ISADevice dev;
  52     MemoryRegion io;
  53     uint8_t cmos_data[128];
  54     uint8_t cmos_index;
  55     struct tm current_tm;
  56     int32_t base_year;
  57     qemu_irq irq;
  58     qemu_irq sqw_irq;
  59     int it_shift;
  60     /* periodic timer */
  61     QEMUTimer *periodic_timer;
  62     int64_t next_periodic_time;
  63     /* second update */
  64     int64_t next_second_time;
  65     uint16_t irq_reinject_on_ack_count;
  66     uint32_t irq_coalesced;
  67     uint32_t period;
  68     QEMUTimer *coalesced_timer;
  69     QEMUTimer *second_timer;
  70     QEMUTimer *second_timer2;
  71     Notifier clock_reset_notifier;
  72     LostTickPolicy lost_tick_policy;
  73     Notifier suspend_notifier;
  74 } RTCState;
  75
  76 static void rtc_set_time(RTCState *s);
  77 static void rtc_copy_date(RTCState *s);
  78
  79 #ifdef TARGET_I386
  80 static void rtc_coalesced_timer_update(RTCState *s)
  81 {
  82     if (s->irq_coalesced == 0) {
  83         qemu_del_timer(s->coalesced_timer);
  84     } else {
  85         /* divide each RTC interval to 2 - 8 smaller intervals */
  86         int c = MIN(s->irq_coalesced, 7) + 1;
  87         int64_t next_clock = qemu_get_clock_ns(rtc_clock) +
  88             muldiv64(s->period / c, get_ticks_per_sec(), 32768);
  89         qemu_mod_timer(s->coalesced_timer, next_clock);
  90     }
  91 }
  92
  93 static void rtc_coalesced_timer(void *opaque)
  94 {
  95     RTCState *s = opaque;
  96
  97     if (s->irq_coalesced != 0) {
  98         apic_reset_irq_delivered();
  99         s->cmos_data[RTC_REG_C] |= 0xc0;
 100         DPRINTF_C("cmos: injecting from timer\n");
 101         qemu_irq_raise(s->irq);
 102         if (apic_get_irq_delivered()) {
 103             s->irq_coalesced--;
 104             DPRINTF_C("cmos: coalesced irqs decreased to %d\n",
 105                       s->irq_coalesced);
 106         }
 107     }
 108
 109     rtc_coalesced_timer_update(s);
 110 }
 111 #endif
 112
 113 static void rtc_timer_update(RTCState *s, int64_t current_time)
 114 {
 115     int period_code, period;
 116     int64_t cur_clock, next_irq_clock;
 117
 118     period_code = s->cmos_data[RTC_REG_A] & 0x0f;
 119     if (period_code != 0
 120         && ((s->cmos_data[RTC_REG_B] & REG_B_PIE)
 121             || ((s->cmos_data[RTC_REG_B] & REG_B_SQWE) && s->sqw_irq))) {
 122         if (period_code <= 2)
 123             period_code += 7;
 124         /* period in 32 Khz cycles */
 125         period = 1 << (period_code - 1);
 126 #ifdef TARGET_I386
 127         if (period != s->period) {
 128             s->irq_coalesced = (s->irq_coalesced * s->period) / period;
 129             DPRINTF_C("cmos: coalesced irqs scaled to %d\n", s->irq_coalesced);
 130         }
 131         s->period = period;
 132 #endif
 133         /* compute 32 khz clock */
 134         cur_clock = muldiv64(current_time, 32768, get_ticks_per_sec());
 135         next_irq_clock = (cur_clock & ~(period - 1)) + period;
 136         s->next_periodic_time =
 137             muldiv64(next_irq_clock, get_ticks_per_sec(), 32768) + 1;
 138         qemu_mod_timer(s->periodic_timer, s->next_periodic_time);
 139     } else {
 140 #ifdef TARGET_I386
 141         s->irq_coalesced = 0;
 142 #endif
 143         qemu_del_timer(s->periodic_timer);
 144     }
 145 }
 146
 147 static void rtc_periodic_timer(void *opaque)
 148 {
 149     RTCState *s = opaque;
 150
 151     rtc_timer_update(s, s->next_periodic_time);
 152     s->cmos_data[RTC_REG_C] |= REG_C_PF;
 153     if (s->cmos_data[RTC_REG_B] & REG_B_PIE) {
 154         s->cmos_data[RTC_REG_C] |= REG_C_IRQF;
 155 #ifdef TARGET_I386
 156         if (s->lost_tick_policy == LOST_TICK_SLEW) {
 157             if (s->irq_reinject_on_ack_count >= RTC_REINJECT_ON_ACK_COUNT)
 158                 s->irq_reinject_on_ack_count = 0;
 159             apic_reset_irq_delivered();
 160             qemu_irq_raise(s->irq);
 161             if (!apic_get_irq_delivered()) {
 162                 s->irq_coalesced++;
 163                 rtc_coalesced_timer_update(s);
 164                 DPRINTF_C("cmos: coalesced irqs increased to %d\n",
 165                           s->irq_coalesced);
 166             }
 167         } else
 168 #endif
 169         qemu_irq_raise(s->irq);
 170     }
 171     if (s->cmos_data[RTC_REG_B] & REG_B_SQWE) {
 172         /* Not square wave at all but we don't want 2048Hz interrupts!
 173            Must be seen as a pulse.  */
 174         qemu_irq_raise(s->sqw_irq);
 175     }
 176 }
 177
 178 static void cmos_ioport_write(void *opaque, uint32_t addr, uint32_t data)
 179 {
 180     RTCState *s = opaque;
 181
 182     if ((addr & 1) == 0) {
 183         s->cmos_index = data & 0x7f;
 184     } else {
 185         CMOS_DPRINTF("cmos: write index=0x%02x val=0x%02x\n",
 186                      s->cmos_index, data);
 187         switch(s->cmos_index) {
 188         case RTC_SECONDS_ALARM:
 189         case RTC_MINUTES_ALARM:
 190         case RTC_HOURS_ALARM:
 191             s->cmos_data[s->cmos_index] = data;
 192             break;
 193         case RTC_SECONDS:
 194         case RTC_MINUTES:
 195         case RTC_HOURS:
 196         case RTC_DAY_OF_WEEK:
 197         case RTC_DAY_OF_MONTH:
 198         case RTC_MONTH:
 199         case RTC_YEAR:
 200             s->cmos_data[s->cmos_index] = data;
 201             /* if in set mode, do not update the time */
 202             if (!(s->cmos_data[RTC_REG_B] & REG_B_SET)) {
 203                 rtc_set_time(s);
 204             }
 205             break;
 206         case RTC_REG_A:
 207             /* UIP bit is read only */
 208             s->cmos_data[RTC_REG_A] = (data & ~REG_A_UIP) |
 209                 (s->cmos_data[RTC_REG_A] & REG_A_UIP);
 210             rtc_timer_update(s, qemu_get_clock_ns(rtc_clock));
 211             break;
 212         case RTC_REG_B:
 213             if (data & REG_B_SET) {
 214                 /* set mode: reset UIP mode */
 215                 s->cmos_data[RTC_REG_A] &= ~REG_A_UIP;
 216                 data &= ~REG_B_UIE;
 217             } else {
 218                 /* if disabling set mode, update the time */
 219                 if (s->cmos_data[RTC_REG_B] & REG_B_SET) {
 220                     rtc_set_time(s);
 221                 }
 222             }
 223             if (((s->cmos_data[RTC_REG_B] ^ data) & (REG_B_DM | REG_B_24H)) &&
 224                 !(data & REG_B_SET)) {
 225                 /* If the time format has changed and not in set mode,
 226                    update the registers immediately. */
 227                 s->cmos_data[RTC_REG_B] = data;
 228                 rtc_copy_date(s);
 229             } else {
 230                 s->cmos_data[RTC_REG_B] = data;
 231             }
 232             rtc_timer_update(s, qemu_get_clock_ns(rtc_clock));
 233             break;
 234         case RTC_REG_C:
 235         case RTC_REG_D:
 236             /* cannot write to them */
 237             break;
 238         default:
 239             s->cmos_data[s->cmos_index] = data;
 240             break;
 241         }
 242     }
 243 }
 244
 245 static inline int rtc_to_bcd(RTCState *s, int a)
 246 {
 247     if (s->cmos_data[RTC_REG_B] & REG_B_DM) {
 248         return a;
 249     } else {
 250         return ((a / 10) << 4) | (a % 10);
 251     }
 252 }
 253
 254 static inline int rtc_from_bcd(RTCState *s, int a)
 255 {
 256     if (s->cmos_data[RTC_REG_B] & REG_B_DM) {
 257         return a;
 258     } else {
 259         return ((a >> 4) * 10) + (a & 0x0f);
 260     }
 261 }
 262
 263 static void rtc_set_time(RTCState *s)
 264 {
 265     struct tm *tm = &s->current_tm;
 266
 267     tm->tm_sec = rtc_from_bcd(s, s->cmos_data[RTC_SECONDS]);
 268     tm->tm_min = rtc_from_bcd(s, s->cmos_data[RTC_MINUTES]);
 269     tm->tm_hour = rtc_from_bcd(s, s->cmos_data[RTC_HOURS] & 0x7f);
 270     if (!(s->cmos_data[RTC_REG_B] & REG_B_24H)) {
 271         tm->tm_hour %= 12;
 272         if (s->cmos_data[RTC_HOURS] & 0x80) {
 273             tm->tm_hour += 12;
 274         }
 275     }
 276     tm->tm_wday = rtc_from_bcd(s, s->cmos_data[RTC_DAY_OF_WEEK]) - 1;
 277     tm->tm_mday = rtc_from_bcd(s, s->cmos_data[RTC_DAY_OF_MONTH]);
 278     tm->tm_mon = rtc_from_bcd(s, s->cmos_data[RTC_MONTH]) - 1;
 279     tm->tm_year = rtc_from_bcd(s, s->cmos_data[RTC_YEAR]) + s->base_year - 1900;
 280
 281     rtc_change_mon_event(tm);
 282 }
 283
 284 static void rtc_copy_date(RTCState *s)
 285 {
 286     const struct tm *tm = &s->current_tm;
 287     int year;
 288
 289     s->cmos_data[RTC_SECONDS] = rtc_to_bcd(s, tm->tm_sec);
 290     s->cmos_data[RTC_MINUTES] = rtc_to_bcd(s, tm->tm_min);
 291     if (s->cmos_data[RTC_REG_B] & REG_B_24H) {
 292         /* 24 hour format */
 293         s->cmos_data[RTC_HOURS] = rtc_to_bcd(s, tm->tm_hour);
 294     } else {
 295         /* 12 hour format */
 296         int h = (tm->tm_hour % 12) ? tm->tm_hour % 12 : 12;
 297         s->cmos_data[RTC_HOURS] = rtc_to_bcd(s, h);
 298         if (tm->tm_hour >= 12)
 299             s->cmos_data[RTC_HOURS] |= 0x80;
 300     }
 301     s->cmos_data[RTC_DAY_OF_WEEK] = rtc_to_bcd(s, tm->tm_wday + 1);
 302     s->cmos_data[RTC_DAY_OF_MONTH] = rtc_to_bcd(s, tm->tm_mday);
 303     s->cmos_data[RTC_MONTH] = rtc_to_bcd(s, tm->tm_mon + 1);
 304     year = (tm->tm_year - s->base_year) % 100;
 305     if (year < 0)
 306         year += 100;
 307     s->cmos_data[RTC_YEAR] = rtc_to_bcd(s, year);
 308 }
 309
 310 /* month is between 0 and 11. */
 311 static int get_days_in_month(int month, int year)
 312 {
 313     static const int days_tab[12] = {
 314         31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
 315     };
 316     int d;
 317     if ((unsigned )month >= 12)
 318         return 31;
 319     d = days_tab[month];
 320     if (month == 1) {
 321         if ((year % 4) == 0 && ((year % 100) != 0 || (year % 400) == 0))
 322             d++;
 323     }
 324     return d;
 325 }
 326
 327 /* update 'tm' to the next second */
 328 static void rtc_next_second(struct tm *tm)
 329 {
 330     int days_in_month;
 331
 332     tm->tm_sec++;
 333     if ((unsigned)tm->tm_sec >= 60) {
 334         tm->tm_sec = 0;
 335         tm->tm_min++;
 336         if ((unsigned)tm->tm_min >= 60) {
 337             tm->tm_min = 0;
 338             tm->tm_hour++;
 339             if ((unsigned)tm->tm_hour >= 24) {
 340                 tm->tm_hour = 0;
 341                 /* next day */
 342                 tm->tm_wday++;
 343                 if ((unsigned)tm->tm_wday >= 7)
 344                     tm->tm_wday = 0;
 345                 days_in_month = get_days_in_month(tm->tm_mon,
 346                                                   tm->tm_year + 1900);
 347                 tm->tm_mday++;
 348                 if (tm->tm_mday < 1) {
 349                     tm->tm_mday = 1;
 350                 } else if (tm->tm_mday > days_in_month) {
 351                     tm->tm_mday = 1;
 352                     tm->tm_mon++;
 353                     if (tm->tm_mon >= 12) {
 354                         tm->tm_mon = 0;
 355                         tm->tm_year++;
 356                     }
 357                 }
 358             }
 359         }
 360     }
 361 }
 362
 363
 364 static void rtc_update_second(void *opaque)
 365 {
 366     RTCState *s = opaque;
 367     int64_t delay;
 368
 369     /* if the oscillator is not in normal operation, we do not update */
 370     if ((s->cmos_data[RTC_REG_A] & 0x70) != 0x20) {
 371         s->next_second_time += get_ticks_per_sec();
 372         qemu_mod_timer(s->second_timer, s->next_second_time);
 373     } else {
 374         rtc_next_second(&s->current_tm);
 375
 376         if (!(s->cmos_data[RTC_REG_B] & REG_B_SET)) {
 377             /* update in progress bit */
 378             s->cmos_data[RTC_REG_A] |= REG_A_UIP;
 379         }
 380         /* should be 244 us = 8 / 32768 seconds, but currently the
 381            timers do not have the necessary resolution. */
 382         delay = (get_ticks_per_sec() * 1) / 100;
 383         if (delay < 1)
 384             delay = 1;
 385         qemu_mod_timer(s->second_timer2,
 386                        s->next_second_time + delay);
 387     }
 388 }
 389
 390 static void rtc_update_second2(void *opaque)
 391 {
 392     RTCState *s = opaque;
 393
 394     if (!(s->cmos_data[RTC_REG_B] & REG_B_SET)) {
 395         rtc_copy_date(s);
 396     }
 397
 398     /* check alarm */
 399     if (((s->cmos_data[RTC_SECONDS_ALARM] & 0xc0) == 0xc0 ||
 400          rtc_from_bcd(s, s->cmos_data[RTC_SECONDS_ALARM]) == s->current_tm.tm_sec) &&
 401         ((s->cmos_data[RTC_MINUTES_ALARM] & 0xc0) == 0xc0 ||
 402          rtc_from_bcd(s, s->cmos_data[RTC_MINUTES_ALARM]) == s->current_tm.tm_min) &&
 403         ((s->cmos_data[RTC_HOURS_ALARM] & 0xc0) == 0xc0 ||
 404          rtc_from_bcd(s, s->cmos_data[RTC_HOURS_ALARM]) == s->current_tm.tm_hour)) {
 405
 406         s->cmos_data[RTC_REG_C] |= REG_C_AF;
 407         if (s->cmos_data[RTC_REG_B] & REG_B_AIE) {
 408             qemu_system_wakeup_request(QEMU_WAKEUP_REASON_RTC);
 409             qemu_irq_raise(s->irq);
 410             s->cmos_data[RTC_REG_C] |= REG_C_IRQF;
 411         }
 412     }
 413
 414     /* update ended interrupt */
 415     s->cmos_data[RTC_REG_C] |= REG_C_UF;
 416     if (s->cmos_data[RTC_REG_B] & REG_B_UIE) {
 417         s->cmos_data[RTC_REG_C] |= REG_C_IRQF;
 418         qemu_irq_raise(s->irq);
 419     }
 420
 421     /* clear update in progress bit */
 422     s->cmos_data[RTC_REG_A] &= ~REG_A_UIP;
 423
 424     s->next_second_time += get_ticks_per_sec();
 425     qemu_mod_timer(s->second_timer, s->next_second_time);
 426 }
 427
 428 static uint32_t cmos_ioport_read(void *opaque, uint32_t addr)
 429 {
 430     RTCState *s = opaque;
 431     int ret;
 432     if ((addr & 1) == 0) {
 433         return 0xff;
 434     } else {
 435         switch(s->cmos_index) {
 436         case RTC_SECONDS:
 437         case RTC_MINUTES:
 438         case RTC_HOURS:
 439         case RTC_DAY_OF_WEEK:
 440         case RTC_DAY_OF_MONTH:
 441         case RTC_MONTH:
 442         case RTC_YEAR:
 443             ret = s->cmos_data[s->cmos_index];
 444             break;
 445         case RTC_REG_A:
 446             ret = s->cmos_data[s->cmos_index];
 447             break;
 448         case RTC_REG_C:
 449             ret = s->cmos_data[s->cmos_index];
 450             qemu_irq_lower(s->irq);
 451             s->cmos_data[RTC_REG_C] = 0x00;
 452 #ifdef TARGET_I386
 453             if(s->irq_coalesced &&
 454                     (s->cmos_data[RTC_REG_B] & REG_B_PIE) &&
 455                     s->irq_reinject_on_ack_count < RTC_REINJECT_ON_ACK_COUNT) {
 456                 s->irq_reinject_on_ack_count++;
 457                 s->cmos_data[RTC_REG_C] |= REG_C_IRQF | REG_C_PF;
 458                 apic_reset_irq_delivered();
 459                 DPRINTF_C("cmos: injecting on ack\n");
 460                 qemu_irq_raise(s->irq);
 461                 if (apic_get_irq_delivered()) {
 462                     s->irq_coalesced--;
 463                     DPRINTF_C("cmos: coalesced irqs decreased to %d\n",
 464                               s->irq_coalesced);
 465                 }
 466             }
 467 #endif
 468             break;
 469         default:
 470             ret = s->cmos_data[s->cmos_index];
 471             break;
 472         }
 473         CMOS_DPRINTF("cmos: read index=0x%02x val=0x%02x\n",
 474                      s->cmos_index, ret);
 475         return ret;
 476     }
 477 }
 478
 479 void rtc_set_memory(ISADevice *dev, int addr, int val)
 480 {
 481     RTCState *s = DO_UPCAST(RTCState, dev, dev);
 482     if (addr >= 0 && addr <= 127)
 483         s->cmos_data[addr] = val;
 484 }
 485
 486 void rtc_set_date(ISADevice *dev, const struct tm *tm)
 487 {
 488     RTCState *s = DO_UPCAST(RTCState, dev, dev);
 489     s->current_tm = *tm;
 490     rtc_copy_date(s);
 491 }
 492
 493 /* PC cmos mappings */
 494 #define REG_IBM_CENTURY_BYTE        0x32
 495 #define REG_IBM_PS2_CENTURY_BYTE    0x37
 496
 497 static void rtc_set_date_from_host(ISADevice *dev)
 498 {
 499     RTCState *s = DO_UPCAST(RTCState, dev, dev);
 500     struct tm tm;
 501     int val;
 502
 503     /* set the CMOS date */
 504     qemu_get_timedate(&tm, 0);
 505     rtc_set_date(dev, &tm);
 506
 507     val = rtc_to_bcd(s, (tm.tm_year / 100) + 19);
 508     rtc_set_memory(dev, REG_IBM_CENTURY_BYTE, val);
 509     rtc_set_memory(dev, REG_IBM_PS2_CENTURY_BYTE, val);
 510 }
 511
 512 static int rtc_post_load(void *opaque, int version_id)
 513 {
 514 #ifdef TARGET_I386
 515     RTCState *s = opaque;
 516
 517     if (version_id >= 2) {
 518         if (s->lost_tick_policy == LOST_TICK_SLEW) {
 519             rtc_coalesced_timer_update(s);
 520         }
 521     }
 522 #endif
 523     return 0;
 524 }
 525
 526 static const VMStateDescription vmstate_rtc = {
 527     .name = "mc146818rtc",
 528     .version_id = 2,
 529     .minimum_version_id = 1,
 530     .minimum_version_id_old = 1,
 531     .post_load = rtc_post_load,
 532     .fields      = (VMStateField []) {
 533         VMSTATE_BUFFER(cmos_data, RTCState),
 534         VMSTATE_UINT8(cmos_index, RTCState),
 535         VMSTATE_INT32(current_tm.tm_sec, RTCState),
 536         VMSTATE_INT32(current_tm.tm_min, RTCState),
 537         VMSTATE_INT32(current_tm.tm_hour, RTCState),
 538         VMSTATE_INT32(current_tm.tm_wday, RTCState),
 539         VMSTATE_INT32(current_tm.tm_mday, RTCState),
 540         VMSTATE_INT32(current_tm.tm_mon, RTCState),
 541         VMSTATE_INT32(current_tm.tm_year, RTCState),
 542         VMSTATE_TIMER(periodic_timer, RTCState),
 543         VMSTATE_INT64(next_periodic_time, RTCState),
 544         VMSTATE_INT64(next_second_time, RTCState),
 545         VMSTATE_TIMER(second_timer, RTCState),
 546         VMSTATE_TIMER(second_timer2, RTCState),
 547         VMSTATE_UINT32_V(irq_coalesced, RTCState, 2),
 548         VMSTATE_UINT32_V(period, RTCState, 2),
 549         VMSTATE_END_OF_LIST()
 550     }
 551 };
 552
 553 static void rtc_notify_clock_reset(Notifier *notifier, void *data)
 554 {
 555     RTCState *s = container_of(notifier, RTCState, clock_reset_notifier);
 556     int64_t now = *(int64_t *)data;
 557
 558     rtc_set_date_from_host(&s->dev);
 559     s->next_second_time = now + (get_ticks_per_sec() * 99) / 100;
 560     qemu_mod_timer(s->second_timer2, s->next_second_time);
 561     rtc_timer_update(s, now);
 562 #ifdef TARGET_I386
 563     if (s->lost_tick_policy == LOST_TICK_SLEW) {
 564         rtc_coalesced_timer_update(s);
 565     }
 566 #endif
 567 }
 568
 569 /* set CMOS shutdown status register (index 0xF) as S3_resume(0xFE)
 570    BIOS will read it and start S3 resume at POST Entry */
 571 static void rtc_notify_suspend(Notifier *notifier, void *data)
 572 {
 573     RTCState *s = container_of(notifier, RTCState, suspend_notifier);
 574     rtc_set_memory(&s->dev, 0xF, 0xFE);
 575 }
 576
 577 static void rtc_reset(void *opaque)
 578 {
 579     RTCState *s = opaque;
 580
 581     s->cmos_data[RTC_REG_B] &= ~(REG_B_PIE | REG_B_AIE | REG_B_SQWE);
 582     s->cmos_data[RTC_REG_C] &= ~(REG_C_UF | REG_C_IRQF | REG_C_PF | REG_C_AF);
 583
 584     qemu_irq_lower(s->irq);
 585
 586 #ifdef TARGET_I386
 587     if (s->lost_tick_policy == LOST_TICK_SLEW) {
 588         s->irq_coalesced = 0;
 589     }
 590 #endif
 591 }
 592
 593 static const MemoryRegionPortio cmos_portio[] = {
 594     {0, 2, 1, .read = cmos_ioport_read, .write = cmos_ioport_write },
 595     PORTIO_END_OF_LIST(),
 596 };
 597
 598 static const MemoryRegionOps cmos_ops = {
 599     .old_portio = cmos_portio
 600 };
 601
 602 static void rtc_get_date(Object *obj, Visitor *v, void *opaque,
 603                          const char *name, Error **errp)
 604 {
 605     ISADevice *isa = ISA_DEVICE(obj);
 606     RTCState *s = DO_UPCAST(RTCState, dev, isa);
 607
 608     visit_start_struct(v, NULL, "struct tm", name, 0, errp);
 609     visit_type_int32(v, &s->current_tm.tm_year, "tm_year", errp);
 610     visit_type_int32(v, &s->current_tm.tm_mon, "tm_mon", errp);
 611     visit_type_int32(v, &s->current_tm.tm_mday, "tm_mday", errp);
 612     visit_type_int32(v, &s->current_tm.tm_hour, "tm_hour", errp);
 613     visit_type_int32(v, &s->current_tm.tm_min, "tm_min", errp);
 614     visit_type_int32(v, &s->current_tm.tm_sec, "tm_sec", errp);
 615     visit_end_struct(v, errp);
 616 }
 617
 618 static int rtc_initfn(ISADevice *dev)
 619 {
 620     RTCState *s = DO_UPCAST(RTCState, dev, dev);
 621     int base = 0x70;
 622
 623     s->cmos_data[RTC_REG_A] = 0x26;
 624     s->cmos_data[RTC_REG_B] = 0x02;
 625     s->cmos_data[RTC_REG_C] = 0x00;
 626     s->cmos_data[RTC_REG_D] = 0x80;
 627
 628     rtc_set_date_from_host(dev);
 629
 630 #ifdef TARGET_I386
 631     switch (s->lost_tick_policy) {
 632     case LOST_TICK_SLEW:
 633         s->coalesced_timer =
 634             qemu_new_timer_ns(rtc_clock, rtc_coalesced_timer, s);
 635         break;
 636     case LOST_TICK_DISCARD:
 637         break;
 638     default:
 639         return -EINVAL;
 640     }
 641 #endif
 642
 643     s->periodic_timer = qemu_new_timer_ns(rtc_clock, rtc_periodic_timer, s);
 644     s->second_timer = qemu_new_timer_ns(rtc_clock, rtc_update_second, s);
 645     s->second_timer2 = qemu_new_timer_ns(rtc_clock, rtc_update_second2, s);
 646
 647     s->clock_reset_notifier.notify = rtc_notify_clock_reset;
 648     qemu_register_clock_reset_notifier(rtc_clock, &s->clock_reset_notifier);
 649
 650     s->suspend_notifier.notify = rtc_notify_suspend;
 651     qemu_register_suspend_notifier(&s->suspend_notifier);
 652
 653     s->next_second_time =
 654         qemu_get_clock_ns(rtc_clock) + (get_ticks_per_sec() * 99) / 100;
 655     qemu_mod_timer(s->second_timer2, s->next_second_time);
 656
 657     memory_region_init_io(&s->io, &cmos_ops, s, "rtc", 2);
 658     isa_register_ioport(dev, &s->io, base);
 659
 660     qdev_set_legacy_instance_id(&dev->qdev, base, 2);
 661     qemu_register_reset(rtc_reset, s);
 662
 663     object_property_add(OBJECT(s), "date", "struct tm",
 664                         rtc_get_date, NULL, NULL, s, NULL);
 665
 666     return 0;
 667 }
 668
 669 ISADevice *rtc_init(ISABus *bus, int base_year, qemu_irq intercept_irq)
 670 {
 671     ISADevice *dev;
 672     RTCState *s;
 673
 674     dev = isa_create(bus, "mc146818rtc");
 675     s = DO_UPCAST(RTCState, dev, dev);
 676     qdev_prop_set_int32(&dev->qdev, "base_year", base_year);
 677     qdev_init_nofail(&dev->qdev);
 678     if (intercept_irq) {
 679         s->irq = intercept_irq;
 680     } else {
 681         isa_init_irq(dev, &s->irq, RTC_ISA_IRQ);
 682     }
 683     return dev;
 684 }
 685
 686 static Property mc146818rtc_properties[] = {
 687     DEFINE_PROP_INT32("base_year", RTCState, base_year, 1980),
 688     DEFINE_PROP_LOSTTICKPOLICY("lost_tick_policy", RTCState,
 689                                lost_tick_policy, LOST_TICK_DISCARD),
 690     DEFINE_PROP_END_OF_LIST(),
 691 };
 692
 693 static void rtc_class_initfn(ObjectClass *klass, void *data)
 694 {
 695     DeviceClass *dc = DEVICE_CLASS(klass);
 696     ISADeviceClass *ic = ISA_DEVICE_CLASS(klass);
 697     ic->init = rtc_initfn;
 698     dc->no_user = 1;
 699     dc->vmsd = &vmstate_rtc;
 700     dc->props = mc146818rtc_properties;
 701 }
 702
 703 static TypeInfo mc146818rtc_info = {
 704     .name          = "mc146818rtc",
 705     .parent        = TYPE_ISA_DEVICE,
 706     .instance_size = sizeof(RTCState),
 707     .class_init    = rtc_class_initfn,
 708 };
 709
 710 static void mc146818rtc_register_types(void)
 711 {
 712     type_register_static(&mc146818rtc_info);
 713 }
 714
 715 type_init(mc146818rtc_register_types)