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 "isa.h"
  29
  30 //#define DEBUG_CMOS
  31
  32 #define RTC_SECONDS             0
  33 #define RTC_SECONDS_ALARM       1
  34 #define RTC_MINUTES             2
  35 #define RTC_MINUTES_ALARM       3
  36 #define RTC_HOURS               4
  37 #define RTC_HOURS_ALARM         5
  38 #define RTC_ALARM_DONT_CARE    0xC0
  39
  40 #define RTC_DAY_OF_WEEK         6
  41 #define RTC_DAY_OF_MONTH        7
  42 #define RTC_MONTH               8
  43 #define RTC_YEAR                9
  44
  45 #define RTC_REG_A               10
  46 #define RTC_REG_B               11
  47 #define RTC_REG_C               12
  48 #define RTC_REG_D               13
  49
  50 #define REG_A_UIP 0x80
  51
  52 #define REG_B_SET 0x80
  53 #define REG_B_PIE 0x40
  54 #define REG_B_AIE 0x20
  55 #define REG_B_UIE 0x10
  56
  57 struct RTCState {
  58     uint8_t cmos_data[128];
  59     uint8_t cmos_index;
  60     struct tm current_tm;
  61     qemu_irq irq;
  62     target_phys_addr_t base;
  63     int it_shift;
  64     /* periodic timer */
  65     QEMUTimer *periodic_timer;
  66     int64_t next_periodic_time;
  67     /* second update */
  68     int64_t next_second_time;
  69     QEMUTimer *second_timer;
  70     QEMUTimer *second_timer2;
  71 };
  72
  73 static void rtc_set_time(RTCState *s);
  74 static void rtc_copy_date(RTCState *s);
  75
  76 static void rtc_timer_update(RTCState *s, int64_t current_time)
  77 {
  78     int period_code, period;
  79     int64_t cur_clock, next_irq_clock;
  80
  81     period_code = s->cmos_data[RTC_REG_A] & 0x0f;
  82     if (period_code != 0 &&
  83         (s->cmos_data[RTC_REG_B] & REG_B_PIE)) {
  84         if (period_code <= 2)
  85             period_code += 7;
  86         /* period in 32 Khz cycles */
  87         period = 1 << (period_code - 1);
  88         /* compute 32 khz clock */
  89         cur_clock = muldiv64(current_time, 32768, ticks_per_sec);
  90         next_irq_clock = (cur_clock & ~(period - 1)) + period;
  91         s->next_periodic_time = muldiv64(next_irq_clock, ticks_per_sec, 32768) + 1;
  92         qemu_mod_timer(s->periodic_timer, s->next_periodic_time);
  93     } else {
  94         qemu_del_timer(s->periodic_timer);
  95     }
  96 }
  97
  98 static void rtc_periodic_timer(void *opaque)
  99 {
 100     RTCState *s = opaque;
 101
 102     rtc_timer_update(s, s->next_periodic_time);
 103     s->cmos_data[RTC_REG_C] |= 0xc0;
 104     qemu_irq_raise(s->irq);
 105 }
 106
 107 static void cmos_ioport_write(void *opaque, uint32_t addr, uint32_t data)
 108 {
 109     RTCState *s = opaque;
 110
 111     if ((addr & 1) == 0) {
 112         s->cmos_index = data & 0x7f;
 113     } else {
 114 #ifdef DEBUG_CMOS
 115         printf("cmos: write index=0x%02x val=0x%02x\n",
 116                s->cmos_index, data);
 117 #endif
 118         switch(s->cmos_index) {
 119         case RTC_SECONDS_ALARM:
 120         case RTC_MINUTES_ALARM:
 121         case RTC_HOURS_ALARM:
 122             /* XXX: not supported */
 123             s->cmos_data[s->cmos_index] = data;
 124             break;
 125         case RTC_SECONDS:
 126         case RTC_MINUTES:
 127         case RTC_HOURS:
 128         case RTC_DAY_OF_WEEK:
 129         case RTC_DAY_OF_MONTH:
 130         case RTC_MONTH:
 131         case RTC_YEAR:
 132             s->cmos_data[s->cmos_index] = data;
 133             /* if in set mode, do not update the time */
 134             if (!(s->cmos_data[RTC_REG_B] & REG_B_SET)) {
 135                 rtc_set_time(s);
 136             }
 137             break;
 138         case RTC_REG_A:
 139             /* UIP bit is read only */
 140             s->cmos_data[RTC_REG_A] = (data & ~REG_A_UIP) |
 141                 (s->cmos_data[RTC_REG_A] & REG_A_UIP);
 142             rtc_timer_update(s, qemu_get_clock(vm_clock));
 143             break;
 144         case RTC_REG_B:
 145             if (data & REG_B_SET) {
 146                 /* set mode: reset UIP mode */
 147                 s->cmos_data[RTC_REG_A] &= ~REG_A_UIP;
 148                 data &= ~REG_B_UIE;
 149             } else {
 150                 /* if disabling set mode, update the time */
 151                 if (s->cmos_data[RTC_REG_B] & REG_B_SET) {
 152                     rtc_set_time(s);
 153                 }
 154             }
 155             s->cmos_data[RTC_REG_B] = data;
 156             rtc_timer_update(s, qemu_get_clock(vm_clock));
 157             break;
 158         case RTC_REG_C:
 159         case RTC_REG_D:
 160             /* cannot write to them */
 161             break;
 162         default:
 163             s->cmos_data[s->cmos_index] = data;
 164             break;
 165         }
 166     }
 167 }
 168
 169 static inline int to_bcd(RTCState *s, int a)
 170 {
 171     if (s->cmos_data[RTC_REG_B] & 0x04) {
 172         return a;
 173     } else {
 174         return ((a / 10) << 4) | (a % 10);
 175     }
 176 }
 177
 178 static inline int from_bcd(RTCState *s, int a)
 179 {
 180     if (s->cmos_data[RTC_REG_B] & 0x04) {
 181         return a;
 182     } else {
 183         return ((a >> 4) * 10) + (a & 0x0f);
 184     }
 185 }
 186
 187 static void rtc_set_time(RTCState *s)
 188 {
 189     struct tm *tm = &s->current_tm;
 190
 191     tm->tm_sec = from_bcd(s, s->cmos_data[RTC_SECONDS]);
 192     tm->tm_min = from_bcd(s, s->cmos_data[RTC_MINUTES]);
 193     tm->tm_hour = from_bcd(s, s->cmos_data[RTC_HOURS] & 0x7f);
 194     if (!(s->cmos_data[RTC_REG_B] & 0x02) &&
 195         (s->cmos_data[RTC_HOURS] & 0x80)) {
 196         tm->tm_hour += 12;
 197     }
 198     tm->tm_wday = from_bcd(s, s->cmos_data[RTC_DAY_OF_WEEK]);
 199     tm->tm_mday = from_bcd(s, s->cmos_data[RTC_DAY_OF_MONTH]);
 200     tm->tm_mon = from_bcd(s, s->cmos_data[RTC_MONTH]) - 1;
 201     tm->tm_year = from_bcd(s, s->cmos_data[RTC_YEAR]) + 100;
 202 }
 203
 204 static void rtc_copy_date(RTCState *s)
 205 {
 206     const struct tm *tm = &s->current_tm;
 207
 208     s->cmos_data[RTC_SECONDS] = to_bcd(s, tm->tm_sec);
 209     s->cmos_data[RTC_MINUTES] = to_bcd(s, tm->tm_min);
 210     if (s->cmos_data[RTC_REG_B] & 0x02) {
 211         /* 24 hour format */
 212         s->cmos_data[RTC_HOURS] = to_bcd(s, tm->tm_hour);
 213     } else {
 214         /* 12 hour format */
 215         s->cmos_data[RTC_HOURS] = to_bcd(s, tm->tm_hour % 12);
 216         if (tm->tm_hour >= 12)
 217             s->cmos_data[RTC_HOURS] |= 0x80;
 218     }
 219     s->cmos_data[RTC_DAY_OF_WEEK] = to_bcd(s, tm->tm_wday);
 220     s->cmos_data[RTC_DAY_OF_MONTH] = to_bcd(s, tm->tm_mday);
 221     s->cmos_data[RTC_MONTH] = to_bcd(s, tm->tm_mon + 1);
 222     s->cmos_data[RTC_YEAR] = to_bcd(s, tm->tm_year % 100);
 223 }
 224
 225 /* month is between 0 and 11. */
 226 static int get_days_in_month(int month, int year)
 227 {
 228     static const int days_tab[12] = {
 229         31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
 230     };
 231     int d;
 232     if ((unsigned )month >= 12)
 233         return 31;
 234     d = days_tab[month];
 235     if (month == 1) {
 236         if ((year % 4) == 0 && ((year % 100) != 0 || (year % 400) == 0))
 237             d++;
 238     }
 239     return d;
 240 }
 241
 242 /* update 'tm' to the next second */
 243 static void rtc_next_second(struct tm *tm)
 244 {
 245     int days_in_month;
 246
 247     tm->tm_sec++;
 248     if ((unsigned)tm->tm_sec >= 60) {
 249         tm->tm_sec = 0;
 250         tm->tm_min++;
 251         if ((unsigned)tm->tm_min >= 60) {
 252             tm->tm_min = 0;
 253             tm->tm_hour++;
 254             if ((unsigned)tm->tm_hour >= 24) {
 255                 tm->tm_hour = 0;
 256                 /* next day */
 257                 tm->tm_wday++;
 258                 if ((unsigned)tm->tm_wday >= 7)
 259                     tm->tm_wday = 0;
 260                 days_in_month = get_days_in_month(tm->tm_mon,
 261                                                   tm->tm_year + 1900);
 262                 tm->tm_mday++;
 263                 if (tm->tm_mday < 1) {
 264                     tm->tm_mday = 1;
 265                 } else if (tm->tm_mday > days_in_month) {
 266                     tm->tm_mday = 1;
 267                     tm->tm_mon++;
 268                     if (tm->tm_mon >= 12) {
 269                         tm->tm_mon = 0;
 270                         tm->tm_year++;
 271                     }
 272                 }
 273             }
 274         }
 275     }
 276 }
 277
 278
 279 static void rtc_update_second(void *opaque)
 280 {
 281     RTCState *s = opaque;
 282     int64_t delay;
 283
 284     /* if the oscillator is not in normal operation, we do not update */
 285     if ((s->cmos_data[RTC_REG_A] & 0x70) != 0x20) {
 286         s->next_second_time += ticks_per_sec;
 287         qemu_mod_timer(s->second_timer, s->next_second_time);
 288     } else {
 289         rtc_next_second(&s->current_tm);
 290
 291         if (!(s->cmos_data[RTC_REG_B] & REG_B_SET)) {
 292             /* update in progress bit */
 293             s->cmos_data[RTC_REG_A] |= REG_A_UIP;
 294         }
 295         /* should be 244 us = 8 / 32768 seconds, but currently the
 296            timers do not have the necessary resolution. */
 297         delay = (ticks_per_sec * 1) / 100;
 298         if (delay < 1)
 299             delay = 1;
 300         qemu_mod_timer(s->second_timer2,
 301                        s->next_second_time + delay);
 302     }
 303 }
 304
 305 static void rtc_update_second2(void *opaque)
 306 {
 307     RTCState *s = opaque;
 308
 309     if (!(s->cmos_data[RTC_REG_B] & REG_B_SET)) {
 310         rtc_copy_date(s);
 311     }
 312
 313     /* check alarm */
 314     if (s->cmos_data[RTC_REG_B] & REG_B_AIE) {
 315         if (((s->cmos_data[RTC_SECONDS_ALARM] & 0xc0) == 0xc0 ||
 316              s->cmos_data[RTC_SECONDS_ALARM] == s->current_tm.tm_sec) &&
 317             ((s->cmos_data[RTC_MINUTES_ALARM] & 0xc0) == 0xc0 ||
 318              s->cmos_data[RTC_MINUTES_ALARM] == s->current_tm.tm_mon) &&
 319             ((s->cmos_data[RTC_HOURS_ALARM] & 0xc0) == 0xc0 ||
 320              s->cmos_data[RTC_HOURS_ALARM] == s->current_tm.tm_hour)) {
 321
 322             s->cmos_data[RTC_REG_C] |= 0xa0;
 323             qemu_irq_raise(s->irq);
 324         }
 325     }
 326
 327     /* update ended interrupt */
 328     if (s->cmos_data[RTC_REG_B] & REG_B_UIE) {
 329         s->cmos_data[RTC_REG_C] |= 0x90;
 330         qemu_irq_raise(s->irq);
 331     }
 332
 333     /* clear update in progress bit */
 334     s->cmos_data[RTC_REG_A] &= ~REG_A_UIP;
 335
 336     s->next_second_time += ticks_per_sec;
 337     qemu_mod_timer(s->second_timer, s->next_second_time);
 338 }
 339
 340 static uint32_t cmos_ioport_read(void *opaque, uint32_t addr)
 341 {
 342     RTCState *s = opaque;
 343     int ret;
 344     if ((addr & 1) == 0) {
 345         return 0xff;
 346     } else {
 347         switch(s->cmos_index) {
 348         case RTC_SECONDS:
 349         case RTC_MINUTES:
 350         case RTC_HOURS:
 351         case RTC_DAY_OF_WEEK:
 352         case RTC_DAY_OF_MONTH:
 353         case RTC_MONTH:
 354         case RTC_YEAR:
 355             ret = s->cmos_data[s->cmos_index];
 356             break;
 357         case RTC_REG_A:
 358             ret = s->cmos_data[s->cmos_index];
 359             break;
 360         case RTC_REG_C:
 361             ret = s->cmos_data[s->cmos_index];
 362             qemu_irq_lower(s->irq);
 363             s->cmos_data[RTC_REG_C] = 0x00;
 364             break;
 365         default:
 366             ret = s->cmos_data[s->cmos_index];
 367             break;
 368         }
 369 #ifdef DEBUG_CMOS
 370         printf("cmos: read index=0x%02x val=0x%02x\n",
 371                s->cmos_index, ret);
 372 #endif
 373         return ret;
 374     }
 375 }
 376
 377 void rtc_set_memory(RTCState *s, int addr, int val)
 378 {
 379     if (addr >= 0 && addr <= 127)
 380         s->cmos_data[addr] = val;
 381 }
 382
 383 void rtc_set_date(RTCState *s, const struct tm *tm)
 384 {
 385     s->current_tm = *tm;
 386     rtc_copy_date(s);
 387 }
 388
 389 /* PC cmos mappings */
 390 #define REG_IBM_CENTURY_BYTE        0x32
 391 #define REG_IBM_PS2_CENTURY_BYTE    0x37
 392
 393 static void rtc_set_date_from_host(RTCState *s)
 394 {
 395     struct tm tm;
 396     int val;
 397
 398     /* set the CMOS date */
 399     qemu_get_timedate(&tm, 0);
 400     rtc_set_date(s, &tm);
 401
 402     val = to_bcd(s, (tm.tm_year / 100) + 19);
 403     rtc_set_memory(s, REG_IBM_CENTURY_BYTE, val);
 404     rtc_set_memory(s, REG_IBM_PS2_CENTURY_BYTE, val);
 405 }
 406
 407 static void rtc_save(QEMUFile *f, void *opaque)
 408 {
 409     RTCState *s = opaque;
 410
 411     qemu_put_buffer(f, s->cmos_data, 128);
 412     qemu_put_8s(f, &s->cmos_index);
 413
 414     qemu_put_be32(f, s->current_tm.tm_sec);
 415     qemu_put_be32(f, s->current_tm.tm_min);
 416     qemu_put_be32(f, s->current_tm.tm_hour);
 417     qemu_put_be32(f, s->current_tm.tm_wday);
 418     qemu_put_be32(f, s->current_tm.tm_mday);
 419     qemu_put_be32(f, s->current_tm.tm_mon);
 420     qemu_put_be32(f, s->current_tm.tm_year);
 421
 422     qemu_put_timer(f, s->periodic_timer);
 423     qemu_put_be64(f, s->next_periodic_time);
 424
 425     qemu_put_be64(f, s->next_second_time);
 426     qemu_put_timer(f, s->second_timer);
 427     qemu_put_timer(f, s->second_timer2);
 428 }
 429
 430 static int rtc_load(QEMUFile *f, void *opaque, int version_id)
 431 {
 432     RTCState *s = opaque;
 433
 434     if (version_id != 1)
 435         return -EINVAL;
 436
 437     qemu_get_buffer(f, s->cmos_data, 128);
 438     qemu_get_8s(f, &s->cmos_index);
 439
 440     s->current_tm.tm_sec=qemu_get_be32(f);
 441     s->current_tm.tm_min=qemu_get_be32(f);
 442     s->current_tm.tm_hour=qemu_get_be32(f);
 443     s->current_tm.tm_wday=qemu_get_be32(f);
 444     s->current_tm.tm_mday=qemu_get_be32(f);
 445     s->current_tm.tm_mon=qemu_get_be32(f);
 446     s->current_tm.tm_year=qemu_get_be32(f);
 447
 448     qemu_get_timer(f, s->periodic_timer);
 449     s->next_periodic_time=qemu_get_be64(f);
 450
 451     s->next_second_time=qemu_get_be64(f);
 452     qemu_get_timer(f, s->second_timer);
 453     qemu_get_timer(f, s->second_timer2);
 454     return 0;
 455 }
 456
 457 RTCState *rtc_init(int base, qemu_irq irq)
 458 {
 459     RTCState *s;
 460
 461     s = qemu_mallocz(sizeof(RTCState));
 462     if (!s)
 463         return NULL;
 464
 465     s->irq = irq;
 466     s->cmos_data[RTC_REG_A] = 0x26;
 467     s->cmos_data[RTC_REG_B] = 0x02;
 468     s->cmos_data[RTC_REG_C] = 0x00;
 469     s->cmos_data[RTC_REG_D] = 0x80;
 470
 471     rtc_set_date_from_host(s);
 472
 473     s->periodic_timer = qemu_new_timer(vm_clock,
 474                                        rtc_periodic_timer, s);
 475     s->second_timer = qemu_new_timer(vm_clock,
 476                                      rtc_update_second, s);
 477     s->second_timer2 = qemu_new_timer(vm_clock,
 478                                       rtc_update_second2, s);
 479
 480     s->next_second_time = qemu_get_clock(vm_clock) + (ticks_per_sec * 99) / 100;
 481     qemu_mod_timer(s->second_timer2, s->next_second_time);
 482
 483     register_ioport_write(base, 2, 1, cmos_ioport_write, s);
 484     register_ioport_read(base, 2, 1, cmos_ioport_read, s);
 485
 486     register_savevm("mc146818rtc", base, 1, rtc_save, rtc_load, s);
 487     return s;
 488 }
 489
 490 /* Memory mapped interface */
 491 static uint32_t cmos_mm_readb (void *opaque, target_phys_addr_t addr)
 492 {
 493     RTCState *s = opaque;
 494
 495     return cmos_ioport_read(s, (addr - s->base) >> s->it_shift) & 0xFF;
 496 }
 497
 498 static void cmos_mm_writeb (void *opaque,
 499                             target_phys_addr_t addr, uint32_t value)
 500 {
 501     RTCState *s = opaque;
 502
 503     cmos_ioport_write(s, (addr - s->base) >> s->it_shift, value & 0xFF);
 504 }
 505
 506 static uint32_t cmos_mm_readw (void *opaque, target_phys_addr_t addr)
 507 {
 508     RTCState *s = opaque;
 509     uint32_t val;
 510
 511     val = cmos_ioport_read(s, (addr - s->base) >> s->it_shift) & 0xFFFF;
 512 #ifdef TARGET_WORDS_BIGENDIAN
 513     val = bswap16(val);
 514 #endif
 515     return val;
 516 }
 517
 518 static void cmos_mm_writew (void *opaque,
 519                             target_phys_addr_t addr, uint32_t value)
 520 {
 521     RTCState *s = opaque;
 522 #ifdef TARGET_WORDS_BIGENDIAN
 523     value = bswap16(value);
 524 #endif
 525     cmos_ioport_write(s, (addr - s->base) >> s->it_shift, value & 0xFFFF);
 526 }
 527
 528 static uint32_t cmos_mm_readl (void *opaque, target_phys_addr_t addr)
 529 {
 530     RTCState *s = opaque;
 531     uint32_t val;
 532
 533     val = cmos_ioport_read(s, (addr - s->base) >> s->it_shift);
 534 #ifdef TARGET_WORDS_BIGENDIAN
 535     val = bswap32(val);
 536 #endif
 537     return val;
 538 }
 539
 540 static void cmos_mm_writel (void *opaque,
 541                             target_phys_addr_t addr, uint32_t value)
 542 {
 543     RTCState *s = opaque;
 544 #ifdef TARGET_WORDS_BIGENDIAN
 545     value = bswap32(value);
 546 #endif
 547     cmos_ioport_write(s, (addr - s->base) >> s->it_shift, value);
 548 }
 549
 550 static CPUReadMemoryFunc *rtc_mm_read[] = {
 551     &cmos_mm_readb,
 552     &cmos_mm_readw,
 553     &cmos_mm_readl,
 554 };
 555
 556 static CPUWriteMemoryFunc *rtc_mm_write[] = {
 557     &cmos_mm_writeb,
 558     &cmos_mm_writew,
 559     &cmos_mm_writel,
 560 };
 561
 562 RTCState *rtc_mm_init(target_phys_addr_t base, int it_shift, qemu_irq irq)
 563 {
 564     RTCState *s;
 565     int io_memory;
 566
 567     s = qemu_mallocz(sizeof(RTCState));
 568     if (!s)
 569         return NULL;
 570
 571     s->irq = irq;
 572     s->cmos_data[RTC_REG_A] = 0x26;
 573     s->cmos_data[RTC_REG_B] = 0x02;
 574     s->cmos_data[RTC_REG_C] = 0x00;
 575     s->cmos_data[RTC_REG_D] = 0x80;
 576     s->base = base;
 577
 578     rtc_set_date_from_host(s);
 579
 580     s->periodic_timer = qemu_new_timer(vm_clock,
 581                                        rtc_periodic_timer, s);
 582     s->second_timer = qemu_new_timer(vm_clock,
 583                                      rtc_update_second, s);
 584     s->second_timer2 = qemu_new_timer(vm_clock,
 585                                       rtc_update_second2, s);
 586
 587     s->next_second_time = qemu_get_clock(vm_clock) + (ticks_per_sec * 99) / 100;
 588     qemu_mod_timer(s->second_timer2, s->next_second_time);
 589
 590     io_memory = cpu_register_io_memory(0, rtc_mm_read, rtc_mm_write, s);
 591     cpu_register_physical_memory(base, 2 << it_shift, io_memory);
 592
 593     register_savevm("mc146818rtc", base, 1, rtc_save, rtc_load, s);
 594     return s;
 595 }