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 "pc.h"
  28 #include "apic.h"
  29 #include "isa.h"
  30 #include "mc146818rtc.h"
  31
  32 //#define DEBUG_CMOS
  33 //#define DEBUG_COALESCED
  34
  35 #ifdef DEBUG_CMOS
  36 # define CMOS_DPRINTF(format, ...)      printf(format, ## __VA_ARGS__)
  37 #else
  38 # define CMOS_DPRINTF(format, ...)      do { } while (0)
  39 #endif
  40
  41 #ifdef DEBUG_COALESCED
  42 # define DPRINTF_C(format, ...)      printf(format, ## __VA_ARGS__)
  43 #else
  44 # define DPRINTF_C(format, ...)      do { } while (0)
  45 #endif
  46
  47 #define RTC_REINJECT_ON_ACK_COUNT 20
  48
  49 #define RTC_SECONDS             0
  50 #define RTC_SECONDS_ALARM       1
  51 #define RTC_MINUTES             2
  52 #define RTC_MINUTES_ALARM       3
  53 #define RTC_HOURS               4
  54 #define RTC_HOURS_ALARM         5
  55 #define RTC_ALARM_DONT_CARE    0xC0
  56
  57 #define RTC_DAY_OF_WEEK         6
  58 #define RTC_DAY_OF_MONTH        7
  59 #define RTC_MONTH               8
  60 #define RTC_YEAR                9
  61
  62 #define RTC_REG_A               10
  63 #define RTC_REG_B               11
  64 #define RTC_REG_C               12
  65 #define RTC_REG_D               13
  66
  67 #define REG_A_UIP 0x80
  68
  69 #define REG_B_SET  0x80
  70 #define REG_B_PIE  0x40
  71 #define REG_B_AIE  0x20
  72 #define REG_B_UIE  0x10
  73 #define REG_B_SQWE 0x08
  74 #define REG_B_DM   0x04
  75 #define REG_B_24H  0x02
  76
  77 #define REG_C_UF   0x10
  78 #define REG_C_IRQF 0x80
  79 #define REG_C_PF   0x40
  80 #define REG_C_AF   0x20
  81
  82 typedef struct RTCState {
  83     ISADevice dev;
  84     uint8_t cmos_data[128];
  85     uint8_t cmos_index;
  86     struct tm current_tm;
  87     int32_t base_year;
  88     qemu_irq irq;
  89     qemu_irq sqw_irq;
  90     int it_shift;
  91     /* periodic timer */
  92     QEMUTimer *periodic_timer;
  93     int64_t next_periodic_time;
  94     /* second update */
  95     int64_t next_second_time;
  96     uint16_t irq_reinject_on_ack_count;
  97     uint32_t irq_coalesced;
  98     uint32_t period;
  99     QEMUTimer *coalesced_timer;
 100     QEMUTimer *second_timer;
 101     QEMUTimer *second_timer2;
 102 } RTCState;
 103
 104 static void rtc_set_time(RTCState *s);
 105 static void rtc_copy_date(RTCState *s);
 106
 107 #ifdef TARGET_I386
 108 static void rtc_coalesced_timer_update(RTCState *s)
 109 {
 110     if (s->irq_coalesced == 0) {
 111         qemu_del_timer(s->coalesced_timer);
 112     } else {
 113         /* divide each RTC interval to 2 - 8 smaller intervals */
 114         int c = MIN(s->irq_coalesced, 7) + 1;
 115         int64_t next_clock = qemu_get_clock_ns(rtc_clock) +
 116             muldiv64(s->period / c, get_ticks_per_sec(), 32768);
 117         qemu_mod_timer(s->coalesced_timer, next_clock);
 118     }
 119 }
 120
 121 static void rtc_coalesced_timer(void *opaque)
 122 {
 123     RTCState *s = opaque;
 124
 125     if (s->irq_coalesced != 0) {
 126         apic_reset_irq_delivered();
 127         s->cmos_data[RTC_REG_C] |= 0xc0;
 128         DPRINTF_C("cmos: injecting from timer\n");
 129         qemu_irq_raise(s->irq);
 130         if (apic_get_irq_delivered()) {
 131             s->irq_coalesced--;
 132             DPRINTF_C("cmos: coalesced irqs decreased to %d\n",
 133                       s->irq_coalesced);
 134         }
 135     }
 136
 137     rtc_coalesced_timer_update(s);
 138 }
 139 #endif
 140
 141 static void rtc_timer_update(RTCState *s, int64_t current_time)
 142 {
 143     int period_code, period;
 144     int64_t cur_clock, next_irq_clock;
 145
 146     period_code = s->cmos_data[RTC_REG_A] & 0x0f;
 147     if (period_code != 0
 148         && ((s->cmos_data[RTC_REG_B] & REG_B_PIE)
 149             || ((s->cmos_data[RTC_REG_B] & REG_B_SQWE) && s->sqw_irq))) {
 150         if (period_code <= 2)
 151             period_code += 7;
 152         /* period in 32 Khz cycles */
 153         period = 1 << (period_code - 1);
 154 #ifdef TARGET_I386
 155         if (period != s->period) {
 156             s->irq_coalesced = (s->irq_coalesced * s->period) / period;
 157             DPRINTF_C("cmos: coalesced irqs scaled to %d\n", s->irq_coalesced);
 158         }
 159         s->period = period;
 160 #endif
 161         /* compute 32 khz clock */
 162         cur_clock = muldiv64(current_time, 32768, get_ticks_per_sec());
 163         next_irq_clock = (cur_clock & ~(period - 1)) + period;
 164         s->next_periodic_time =
 165             muldiv64(next_irq_clock, get_ticks_per_sec(), 32768) + 1;
 166         qemu_mod_timer(s->periodic_timer, s->next_periodic_time);
 167     } else {
 168 #ifdef TARGET_I386
 169         s->irq_coalesced = 0;
 170 #endif
 171         qemu_del_timer(s->periodic_timer);
 172     }
 173 }
 174
 175 static void rtc_periodic_timer(void *opaque)
 176 {
 177     RTCState *s = opaque;
 178
 179     rtc_timer_update(s, s->next_periodic_time);
 180     if (s->cmos_data[RTC_REG_B] & REG_B_PIE) {
 181         s->cmos_data[RTC_REG_C] |= 0xc0;
 182 #ifdef TARGET_I386
 183         if(rtc_td_hack) {
 184             if (s->irq_reinject_on_ack_count >= RTC_REINJECT_ON_ACK_COUNT)
 185                 s->irq_reinject_on_ack_count = 0;
 186             apic_reset_irq_delivered();
 187             qemu_irq_raise(s->irq);
 188             if (!apic_get_irq_delivered()) {
 189                 s->irq_coalesced++;
 190                 rtc_coalesced_timer_update(s);
 191                 DPRINTF_C("cmos: coalesced irqs increased to %d\n",
 192                           s->irq_coalesced);
 193             }
 194         } else
 195 #endif
 196         qemu_irq_raise(s->irq);
 197     }
 198     if (s->cmos_data[RTC_REG_B] & REG_B_SQWE) {
 199         /* Not square wave at all but we don't want 2048Hz interrupts!
 200            Must be seen as a pulse.  */
 201         qemu_irq_raise(s->sqw_irq);
 202     }
 203 }
 204
 205 static void cmos_ioport_write(void *opaque, uint32_t addr, uint32_t data)
 206 {
 207     RTCState *s = opaque;
 208
 209     if ((addr & 1) == 0) {
 210         s->cmos_index = data & 0x7f;
 211     } else {
 212         CMOS_DPRINTF("cmos: write index=0x%02x val=0x%02x\n",
 213                      s->cmos_index, data);
 214         switch(s->cmos_index) {
 215         case RTC_SECONDS_ALARM:
 216         case RTC_MINUTES_ALARM:
 217         case RTC_HOURS_ALARM:
 218             s->cmos_data[s->cmos_index] = data;
 219             break;
 220         case RTC_SECONDS:
 221         case RTC_MINUTES:
 222         case RTC_HOURS:
 223         case RTC_DAY_OF_WEEK:
 224         case RTC_DAY_OF_MONTH:
 225         case RTC_MONTH:
 226         case RTC_YEAR:
 227             s->cmos_data[s->cmos_index] = data;
 228             /* if in set mode, do not update the time */
 229             if (!(s->cmos_data[RTC_REG_B] & REG_B_SET)) {
 230                 rtc_set_time(s);
 231             }
 232             break;
 233         case RTC_REG_A:
 234             /* UIP bit is read only */
 235             s->cmos_data[RTC_REG_A] = (data & ~REG_A_UIP) |
 236                 (s->cmos_data[RTC_REG_A] & REG_A_UIP);
 237             rtc_timer_update(s, qemu_get_clock_ns(rtc_clock));
 238             break;
 239         case RTC_REG_B:
 240             if (data & REG_B_SET) {
 241                 /* set mode: reset UIP mode */
 242                 s->cmos_data[RTC_REG_A] &= ~REG_A_UIP;
 243                 data &= ~REG_B_UIE;
 244             } else {
 245                 /* if disabling set mode, update the time */
 246                 if (s->cmos_data[RTC_REG_B] & REG_B_SET) {
 247                     rtc_set_time(s);
 248                 }
 249             }
 250             if (((s->cmos_data[RTC_REG_B] ^ data) & (REG_B_DM | REG_B_24H)) &&
 251                 !(data & REG_B_SET)) {
 252                 /* If the time format has changed and not in set mode,
 253                    update the registers immediately. */
 254                 s->cmos_data[RTC_REG_B] = data;
 255                 rtc_copy_date(s);
 256             } else {
 257                 s->cmos_data[RTC_REG_B] = data;
 258             }
 259             rtc_timer_update(s, qemu_get_clock_ns(rtc_clock));
 260             break;
 261         case RTC_REG_C:
 262         case RTC_REG_D:
 263             /* cannot write to them */
 264             break;
 265         default:
 266             s->cmos_data[s->cmos_index] = data;
 267             break;
 268         }
 269     }
 270 }
 271
 272 static inline int rtc_to_bcd(RTCState *s, int a)
 273 {
 274     if (s->cmos_data[RTC_REG_B] & REG_B_DM) {
 275         return a;
 276     } else {
 277         return ((a / 10) << 4) | (a % 10);
 278     }
 279 }
 280
 281 static inline int rtc_from_bcd(RTCState *s, int a)
 282 {
 283     if (s->cmos_data[RTC_REG_B] & REG_B_DM) {
 284         return a;
 285     } else {
 286         return ((a >> 4) * 10) + (a & 0x0f);
 287     }
 288 }
 289
 290 static void rtc_set_time(RTCState *s)
 291 {
 292     struct tm *tm = &s->current_tm;
 293
 294     tm->tm_sec = rtc_from_bcd(s, s->cmos_data[RTC_SECONDS]);
 295     tm->tm_min = rtc_from_bcd(s, s->cmos_data[RTC_MINUTES]);
 296     tm->tm_hour = rtc_from_bcd(s, s->cmos_data[RTC_HOURS] & 0x7f);
 297     if (!(s->cmos_data[RTC_REG_B] & REG_B_24H) &&
 298         (s->cmos_data[RTC_HOURS] & 0x80)) {
 299         tm->tm_hour += 12;
 300     }
 301     tm->tm_wday = rtc_from_bcd(s, s->cmos_data[RTC_DAY_OF_WEEK]) - 1;
 302     tm->tm_mday = rtc_from_bcd(s, s->cmos_data[RTC_DAY_OF_MONTH]);
 303     tm->tm_mon = rtc_from_bcd(s, s->cmos_data[RTC_MONTH]) - 1;
 304     tm->tm_year = rtc_from_bcd(s, s->cmos_data[RTC_YEAR]) + s->base_year - 1900;
 305
 306     rtc_change_mon_event(tm);
 307 }
 308
 309 static void rtc_copy_date(RTCState *s)
 310 {
 311     const struct tm *tm = &s->current_tm;
 312     int year;
 313
 314     s->cmos_data[RTC_SECONDS] = rtc_to_bcd(s, tm->tm_sec);
 315     s->cmos_data[RTC_MINUTES] = rtc_to_bcd(s, tm->tm_min);
 316     if (s->cmos_data[RTC_REG_B] & REG_B_24H) {
 317         /* 24 hour format */
 318         s->cmos_data[RTC_HOURS] = rtc_to_bcd(s, tm->tm_hour);
 319     } else {
 320         /* 12 hour format */
 321         s->cmos_data[RTC_HOURS] = rtc_to_bcd(s, tm->tm_hour % 12);
 322         if (tm->tm_hour >= 12)
 323             s->cmos_data[RTC_HOURS] |= 0x80;
 324     }
 325     s->cmos_data[RTC_DAY_OF_WEEK] = rtc_to_bcd(s, tm->tm_wday + 1);
 326     s->cmos_data[RTC_DAY_OF_MONTH] = rtc_to_bcd(s, tm->tm_mday);
 327     s->cmos_data[RTC_MONTH] = rtc_to_bcd(s, tm->tm_mon + 1);
 328     year = (tm->tm_year - s->base_year) % 100;
 329     if (year < 0)
 330         year += 100;
 331     s->cmos_data[RTC_YEAR] = rtc_to_bcd(s, year);
 332 }
 333
 334 /* month is between 0 and 11. */
 335 static int get_days_in_month(int month, int year)
 336 {
 337     static const int days_tab[12] = {
 338         31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
 339     };
 340     int d;
 341     if ((unsigned )month >= 12)
 342         return 31;
 343     d = days_tab[month];
 344     if (month == 1) {
 345         if ((year % 4) == 0 && ((year % 100) != 0 || (year % 400) == 0))
 346             d++;
 347     }
 348     return d;
 349 }
 350
 351 /* update 'tm' to the next second */
 352 static void rtc_next_second(struct tm *tm)
 353 {
 354     int days_in_month;
 355
 356     tm->tm_sec++;
 357     if ((unsigned)tm->tm_sec >= 60) {
 358         tm->tm_sec = 0;
 359         tm->tm_min++;
 360         if ((unsigned)tm->tm_min >= 60) {
 361             tm->tm_min = 0;
 362             tm->tm_hour++;
 363             if ((unsigned)tm->tm_hour >= 24) {
 364                 tm->tm_hour = 0;
 365                 /* next day */
 366                 tm->tm_wday++;
 367                 if ((unsigned)tm->tm_wday >= 7)
 368                     tm->tm_wday = 0;
 369                 days_in_month = get_days_in_month(tm->tm_mon,
 370                                                   tm->tm_year + 1900);
 371                 tm->tm_mday++;
 372                 if (tm->tm_mday < 1) {
 373                     tm->tm_mday = 1;
 374                 } else if (tm->tm_mday > days_in_month) {
 375                     tm->tm_mday = 1;
 376                     tm->tm_mon++;
 377                     if (tm->tm_mon >= 12) {
 378                         tm->tm_mon = 0;
 379                         tm->tm_year++;
 380                     }
 381                 }
 382             }
 383         }
 384     }
 385 }
 386
 387
 388 static void rtc_update_second(void *opaque)
 389 {
 390     RTCState *s = opaque;
 391     int64_t delay;
 392
 393     /* if the oscillator is not in normal operation, we do not update */
 394     if ((s->cmos_data[RTC_REG_A] & 0x70) != 0x20) {
 395         s->next_second_time += get_ticks_per_sec();
 396         qemu_mod_timer(s->second_timer, s->next_second_time);
 397     } else {
 398         rtc_next_second(&s->current_tm);
 399
 400         if (!(s->cmos_data[RTC_REG_B] & REG_B_SET)) {
 401             /* update in progress bit */
 402             s->cmos_data[RTC_REG_A] |= REG_A_UIP;
 403         }
 404         /* should be 244 us = 8 / 32768 seconds, but currently the
 405            timers do not have the necessary resolution. */
 406         delay = (get_ticks_per_sec() * 1) / 100;
 407         if (delay < 1)
 408             delay = 1;
 409         qemu_mod_timer(s->second_timer2,
 410                        s->next_second_time + delay);
 411     }
 412 }
 413
 414 static void rtc_update_second2(void *opaque)
 415 {
 416     RTCState *s = opaque;
 417
 418     if (!(s->cmos_data[RTC_REG_B] & REG_B_SET)) {
 419         rtc_copy_date(s);
 420     }
 421
 422     /* check alarm */
 423     if (s->cmos_data[RTC_REG_B] & REG_B_AIE) {
 424         if (((s->cmos_data[RTC_SECONDS_ALARM] & 0xc0) == 0xc0 ||
 425              rtc_from_bcd(s, s->cmos_data[RTC_SECONDS_ALARM]) == s->current_tm.tm_sec) &&
 426             ((s->cmos_data[RTC_MINUTES_ALARM] & 0xc0) == 0xc0 ||
 427              rtc_from_bcd(s, s->cmos_data[RTC_MINUTES_ALARM]) == s->current_tm.tm_min) &&
 428             ((s->cmos_data[RTC_HOURS_ALARM] & 0xc0) == 0xc0 ||
 429              rtc_from_bcd(s, s->cmos_data[RTC_HOURS_ALARM]) == s->current_tm.tm_hour)) {
 430
 431             s->cmos_data[RTC_REG_C] |= 0xa0;
 432             qemu_irq_raise(s->irq);
 433         }
 434     }
 435
 436     /* update ended interrupt */
 437     s->cmos_data[RTC_REG_C] |= REG_C_UF;
 438     if (s->cmos_data[RTC_REG_B] & REG_B_UIE) {
 439         s->cmos_data[RTC_REG_C] |= REG_C_IRQF;
 440         qemu_irq_raise(s->irq);
 441     }
 442
 443     /* clear update in progress bit */
 444     s->cmos_data[RTC_REG_A] &= ~REG_A_UIP;
 445
 446     s->next_second_time += get_ticks_per_sec();
 447     qemu_mod_timer(s->second_timer, s->next_second_time);
 448 }
 449
 450 static uint32_t cmos_ioport_read(void *opaque, uint32_t addr)
 451 {
 452     RTCState *s = opaque;
 453     int ret;
 454     if ((addr & 1) == 0) {
 455         return 0xff;
 456     } else {
 457         switch(s->cmos_index) {
 458         case RTC_SECONDS:
 459         case RTC_MINUTES:
 460         case RTC_HOURS:
 461         case RTC_DAY_OF_WEEK:
 462         case RTC_DAY_OF_MONTH:
 463         case RTC_MONTH:
 464         case RTC_YEAR:
 465             ret = s->cmos_data[s->cmos_index];
 466             break;
 467         case RTC_REG_A:
 468             ret = s->cmos_data[s->cmos_index];
 469             break;
 470         case RTC_REG_C:
 471             ret = s->cmos_data[s->cmos_index];
 472             qemu_irq_lower(s->irq);
 473 #ifdef TARGET_I386
 474             if(s->irq_coalesced &&
 475                     s->irq_reinject_on_ack_count < RTC_REINJECT_ON_ACK_COUNT) {
 476                 s->irq_reinject_on_ack_count++;
 477                 apic_reset_irq_delivered();
 478                 DPRINTF_C("cmos: injecting on ack\n");
 479                 qemu_irq_raise(s->irq);
 480                 if (apic_get_irq_delivered()) {
 481                     s->irq_coalesced--;
 482                     DPRINTF_C("cmos: coalesced irqs decreased to %d\n",
 483                               s->irq_coalesced);
 484                 }
 485                 break;
 486             }
 487 #endif
 488
 489             s->cmos_data[RTC_REG_C] = 0x00;
 490             break;
 491         default:
 492             ret = s->cmos_data[s->cmos_index];
 493             break;
 494         }
 495         CMOS_DPRINTF("cmos: read index=0x%02x val=0x%02x\n",
 496                      s->cmos_index, ret);
 497         return ret;
 498     }
 499 }
 500
 501 void rtc_set_memory(ISADevice *dev, int addr, int val)
 502 {
 503     RTCState *s = DO_UPCAST(RTCState, dev, dev);
 504     if (addr >= 0 && addr <= 127)
 505         s->cmos_data[addr] = val;
 506 }
 507
 508 void rtc_set_date(ISADevice *dev, const struct tm *tm)
 509 {
 510     RTCState *s = DO_UPCAST(RTCState, dev, dev);
 511     s->current_tm = *tm;
 512     rtc_copy_date(s);
 513 }
 514
 515 /* PC cmos mappings */
 516 #define REG_IBM_CENTURY_BYTE        0x32
 517 #define REG_IBM_PS2_CENTURY_BYTE    0x37
 518
 519 static void rtc_set_date_from_host(ISADevice *dev)
 520 {
 521     RTCState *s = DO_UPCAST(RTCState, dev, dev);
 522     struct tm tm;
 523     int val;
 524
 525     /* set the CMOS date */
 526     qemu_get_timedate(&tm, 0);
 527     rtc_set_date(dev, &tm);
 528
 529     val = rtc_to_bcd(s, (tm.tm_year / 100) + 19);
 530     rtc_set_memory(dev, REG_IBM_CENTURY_BYTE, val);
 531     rtc_set_memory(dev, REG_IBM_PS2_CENTURY_BYTE, val);
 532 }
 533
 534 static int rtc_post_load(void *opaque, int version_id)
 535 {
 536 #ifdef TARGET_I386
 537     RTCState *s = opaque;
 538
 539     if (version_id >= 2) {
 540         if (rtc_td_hack) {
 541             rtc_coalesced_timer_update(s);
 542         }
 543     }
 544 #endif
 545     return 0;
 546 }
 547
 548 static const VMStateDescription vmstate_rtc = {
 549     .name = "mc146818rtc",
 550     .version_id = 2,
 551     .minimum_version_id = 1,
 552     .minimum_version_id_old = 1,
 553     .post_load = rtc_post_load,
 554     .fields      = (VMStateField []) {
 555         VMSTATE_BUFFER(cmos_data, RTCState),
 556         VMSTATE_UINT8(cmos_index, RTCState),
 557         VMSTATE_INT32(current_tm.tm_sec, RTCState),
 558         VMSTATE_INT32(current_tm.tm_min, RTCState),
 559         VMSTATE_INT32(current_tm.tm_hour, RTCState),
 560         VMSTATE_INT32(current_tm.tm_wday, RTCState),
 561         VMSTATE_INT32(current_tm.tm_mday, RTCState),
 562         VMSTATE_INT32(current_tm.tm_mon, RTCState),
 563         VMSTATE_INT32(current_tm.tm_year, RTCState),
 564         VMSTATE_TIMER(periodic_timer, RTCState),
 565         VMSTATE_INT64(next_periodic_time, RTCState),
 566         VMSTATE_INT64(next_second_time, RTCState),
 567         VMSTATE_TIMER(second_timer, RTCState),
 568         VMSTATE_TIMER(second_timer2, RTCState),
 569         VMSTATE_UINT32_V(irq_coalesced, RTCState, 2),
 570         VMSTATE_UINT32_V(period, RTCState, 2),
 571         VMSTATE_END_OF_LIST()
 572     }
 573 };
 574
 575 static void rtc_reset(void *opaque)
 576 {
 577     RTCState *s = opaque;
 578
 579     s->cmos_data[RTC_REG_B] &= ~(REG_B_PIE | REG_B_AIE | REG_B_SQWE);
 580     s->cmos_data[RTC_REG_C] &= ~(REG_C_UF | REG_C_IRQF | REG_C_PF | REG_C_AF);
 581
 582     qemu_irq_lower(s->irq);
 583
 584 #ifdef TARGET_I386
 585     if (rtc_td_hack)
 586             s->irq_coalesced = 0;
 587 #endif
 588 }
 589
 590 static int rtc_initfn(ISADevice *dev)
 591 {
 592     RTCState *s = DO_UPCAST(RTCState, dev, dev);
 593     int base = 0x70;
 594
 595     s->cmos_data[RTC_REG_A] = 0x26;
 596     s->cmos_data[RTC_REG_B] = 0x02;
 597     s->cmos_data[RTC_REG_C] = 0x00;
 598     s->cmos_data[RTC_REG_D] = 0x80;
 599
 600     rtc_set_date_from_host(dev);
 601
 602     s->periodic_timer = qemu_new_timer_ns(rtc_clock, rtc_periodic_timer, s);
 603 #ifdef TARGET_I386
 604     if (rtc_td_hack)
 605         s->coalesced_timer =
 606             qemu_new_timer_ns(rtc_clock, rtc_coalesced_timer, s);
 607 #endif
 608     s->second_timer = qemu_new_timer_ns(rtc_clock, rtc_update_second, s);
 609     s->second_timer2 = qemu_new_timer_ns(rtc_clock, rtc_update_second2, s);
 610
 611     s->next_second_time =
 612         qemu_get_clock_ns(rtc_clock) + (get_ticks_per_sec() * 99) / 100;
 613     qemu_mod_timer(s->second_timer2, s->next_second_time);
 614
 615     register_ioport_write(base, 2, 1, cmos_ioport_write, s);
 616     register_ioport_read(base, 2, 1, cmos_ioport_read, s);
 617     isa_init_ioport_range(dev, base, 2);
 618
 619     qdev_set_legacy_instance_id(&dev->qdev, base, 2);
 620     qemu_register_reset(rtc_reset, s);
 621     return 0;
 622 }
 623
 624 ISADevice *rtc_init(int base_year, qemu_irq intercept_irq)
 625 {
 626     ISADevice *dev;
 627     RTCState *s;
 628
 629     dev = isa_create("mc146818rtc");
 630     s = DO_UPCAST(RTCState, dev, dev);
 631     qdev_prop_set_int32(&dev->qdev, "base_year", base_year);
 632     qdev_init_nofail(&dev->qdev);
 633     if (intercept_irq) {
 634         s->irq = intercept_irq;
 635     } else {
 636         isa_init_irq(dev, &s->irq, RTC_ISA_IRQ);
 637     }
 638     return dev;
 639 }
 640
 641 static ISADeviceInfo mc146818rtc_info = {
 642     .qdev.name     = "mc146818rtc",
 643     .qdev.size     = sizeof(RTCState),
 644     .qdev.no_user  = 1,
 645     .qdev.vmsd     = &vmstate_rtc,
 646     .init          = rtc_initfn,
 647     .qdev.props    = (Property[]) {
 648         DEFINE_PROP_INT32("base_year", RTCState, base_year, 1980),
 649         DEFINE_PROP_END_OF_LIST(),
 650     }
 651 };
 652
 653 static void mc146818rtc_register(void)
 654 {
 655     isa_qdev_register(&mc146818rtc_info);
 656 }
 657 device_init(mc146818rtc_register)