master
c 1,041 lines 32.7 KB
Raw
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
25 #include "qemu/osdep.h"
26 #include "qemu/cutils.h"
27 #include "qemu/module.h"
28 #include "qemu/bcd.h"
29 #include "hw/acpi/acpi_aml_interface.h"
30 #include "hw/intc/kvm_irqcount.h"
31 #include "hw/core/irq.h"
32 #include "hw/core/qdev-properties.h"
33 #include "hw/core/qdev-properties-system.h"
34 #include "qemu/timer.h"
35 #include "system/system.h"
36 #include "system/replay.h"
37 #include "system/reset.h"
38 #include "system/runstate.h"
39 #include "system/rtc.h"
40 #include "hw/rtc/mc146818rtc.h"
41 #include "hw/rtc/mc146818rtc_regs.h"
42 #include "migration/vmstate.h"
43 #include "qapi/error.h"
44 #include "qapi/qapi-events-misc.h"
45 #include "qapi/visitor.h"
46 #include "trace.h"
47
48 //#define DEBUG_COALESCED
49
50 #ifdef DEBUG_COALESCED
51 # define DPRINTF_C(format, ...) printf(format, ## __VA_ARGS__)
52 #else
53 # define DPRINTF_C(format, ...) do { } while (0)
54 #endif
55
56 #define SEC_PER_MIN 60
57 #define MIN_PER_HOUR 60
58 #define SEC_PER_HOUR 3600
59 #define HOUR_PER_DAY 24
60 #define SEC_PER_DAY 86400
61
62 #define RTC_REINJECT_ON_ACK_COUNT 20
63 #define RTC_CLOCK_RATE 32768
64 #define UIP_HOLD_LENGTH (8 * NANOSECONDS_PER_SECOND / 32768)
65
66 #define RTC_ISA_BASE 0x70
67
68 static void rtc_set_time(MC146818RtcState *s);
69 static void rtc_update_time(MC146818RtcState *s);
70 static void rtc_set_cmos(MC146818RtcState *s, const struct tm *tm);
71 static inline int rtc_from_bcd(MC146818RtcState *s, int a);
72 static uint64_t get_next_alarm(MC146818RtcState *s);
73
74 static inline bool rtc_running(MC146818RtcState *s)
75 {
76 return (!(s->cmos_data[RTC_REG_B] & REG_B_SET) &&
77 (s->cmos_data[RTC_REG_A] & 0x70) <= 0x20);
78 }
79
80 /*
81 * Note: get_rtc_ns_since_last_update() does not include the base_rtc seconds
82 * value. This does not matter if the caller only needs the nanoseconds part.
83 */
84 static uint64_t get_rtc_ns_since_last_update(MC146818RtcState *s)
85 {
86 return qemu_clock_get_ns(rtc_clock) - s->last_update + s->offset;
87 }
88
89 static void rtc_coalesced_timer_update(MC146818RtcState *s)
90 {
91 if (s->irq_coalesced == 0) {
92 timer_del(s->coalesced_timer);
93 } else {
94 /* divide each RTC interval to 2 - 8 smaller intervals */
95 int c = MIN(s->irq_coalesced, 7) + 1;
96 int64_t next_clock = qemu_clock_get_ns(rtc_clock) +
97 periodic_clock_to_ns(s->period / c);
98 timer_mod(s->coalesced_timer, next_clock);
99 }
100 }
101
102 void rtc_reset_reinjection(MC146818RtcState *rtc)
103 {
104 rtc->irq_coalesced = 0;
105 }
106
107 static bool rtc_policy_slew_deliver_irq(MC146818RtcState *s)
108 {
109 kvm_reset_irq_delivered();
110 qemu_irq_raise(s->irq);
111 return kvm_get_irq_delivered();
112 }
113
114 static void rtc_coalesced_timer(void *opaque)
115 {
116 MC146818RtcState *s = opaque;
117
118 if (s->irq_coalesced != 0) {
119 s->cmos_data[RTC_REG_C] |= 0xc0;
120 DPRINTF_C("cmos: injecting from timer\n");
121 if (rtc_policy_slew_deliver_irq(s)) {
122 s->irq_coalesced--;
123 DPRINTF_C("cmos: coalesced irqs decreased to %d\n",
124 s->irq_coalesced);
125 }
126 }
127
128 rtc_coalesced_timer_update(s);
129 }
130
131 static uint32_t rtc_periodic_clock_ticks(MC146818RtcState *s)
132 {
133 int period_code;
134
135 if (!(s->cmos_data[RTC_REG_B] & REG_B_PIE)) {
136 return 0;
137 }
138
139 period_code = s->cmos_data[RTC_REG_A] & 0x0f;
140
141 return periodic_period_to_clock(period_code);
142 }
143
144 /*
145 * handle periodic timer. @old_period indicates the periodic timer update
146 * is just due to period adjustment.
147 */
148 static void periodic_timer_update(MC146818RtcState *s, int64_t current_time,
149 uint32_t old_period, bool period_change)
150 {
151 uint32_t period;
152 int64_t cur_clock, next_irq_clock, lost_clock = 0;
153
154 period = rtc_periodic_clock_ticks(s);
155 s->period = period;
156
157 if (!period) {
158 s->irq_coalesced = 0;
159 timer_del(s->periodic_timer);
160 return;
161 }
162
163 /* compute 32 khz clock */
164 cur_clock =
165 muldiv64(current_time, RTC_CLOCK_RATE, NANOSECONDS_PER_SECOND);
166
167 /*
168 * if the periodic timer's update is due to period re-configuration,
169 * we should count the clock since last interrupt.
170 */
171 if (old_period && period_change) {
172 int64_t last_periodic_clock, next_periodic_clock;
173
174 next_periodic_clock = muldiv64(s->next_periodic_time,
175 RTC_CLOCK_RATE, NANOSECONDS_PER_SECOND);
176 last_periodic_clock = next_periodic_clock - old_period;
177 lost_clock = cur_clock - last_periodic_clock;
178 assert(lost_clock >= 0);
179 }
180
181 /*
182 * s->irq_coalesced can change for two reasons:
183 *
184 * a) if one or more periodic timer interrupts have been lost,
185 * lost_clock will be more that a period.
186 *
187 * b) when the period may be reconfigured, we expect the OS to
188 * treat delayed tick as the new period. So, when switching
189 * from a shorter to a longer period, scale down the missing,
190 * because the OS will treat past delayed ticks as longer
191 * (leftovers are put back into lost_clock). When switching
192 * to a shorter period, scale up the missing ticks since the
193 * OS handler will treat past delayed ticks as shorter.
194 */
195 if (s->lost_tick_policy == LOST_TICK_POLICY_SLEW) {
196 uint32_t old_irq_coalesced = s->irq_coalesced;
197
198 lost_clock += old_irq_coalesced * old_period;
199 s->irq_coalesced = lost_clock / s->period;
200 lost_clock %= s->period;
201 if (old_irq_coalesced != s->irq_coalesced ||
202 old_period != s->period) {
203 DPRINTF_C("cmos: coalesced irqs scaled from %d to %d, "
204 "period scaled from %d to %d\n", old_irq_coalesced,
205 s->irq_coalesced, old_period, s->period);
206 rtc_coalesced_timer_update(s);
207 }
208 } else {
209 /*
210 * no way to compensate the interrupt if LOST_TICK_POLICY_SLEW
211 * is not used, we should make the time progress anyway.
212 */
213 lost_clock = MIN(lost_clock, period);
214 }
215
216 assert(lost_clock >= 0 && lost_clock <= period);
217
218 next_irq_clock = cur_clock + period - lost_clock;
219 s->next_periodic_time = periodic_clock_to_ns(next_irq_clock) + 1;
220 timer_mod(s->periodic_timer, s->next_periodic_time);
221 }
222
223 static void rtc_periodic_timer(void *opaque)
224 {
225 MC146818RtcState *s = opaque;
226
227 periodic_timer_update(s, s->next_periodic_time, s->period, false);
228 s->cmos_data[RTC_REG_C] |= REG_C_PF;
229 if (s->cmos_data[RTC_REG_B] & REG_B_PIE) {
230 s->cmos_data[RTC_REG_C] |= REG_C_IRQF;
231 if (s->lost_tick_policy == LOST_TICK_POLICY_SLEW) {
232 if (s->irq_reinject_on_ack_count >= RTC_REINJECT_ON_ACK_COUNT)
233 s->irq_reinject_on_ack_count = 0;
234 if (!rtc_policy_slew_deliver_irq(s)) {
235 s->irq_coalesced++;
236 rtc_coalesced_timer_update(s);
237 DPRINTF_C("cmos: coalesced irqs increased to %d\n",
238 s->irq_coalesced);
239 }
240 } else
241 qemu_irq_raise(s->irq);
242 }
243 }
244
245 /* handle update-ended timer */
246 static void check_update_timer(MC146818RtcState *s)
247 {
248 uint64_t next_update_time;
249 uint64_t guest_nsec;
250 int next_alarm_sec;
251
252 /* From the data sheet: "Holding the dividers in reset prevents
253 * interrupts from operating, while setting the SET bit allows"
254 * them to occur.
255 */
256 if ((s->cmos_data[RTC_REG_A] & 0x60) == 0x60) {
257 assert((s->cmos_data[RTC_REG_A] & REG_A_UIP) == 0);
258 timer_del(s->update_timer);
259 return;
260 }
261
262 guest_nsec = get_rtc_ns_since_last_update(s) % NANOSECONDS_PER_SECOND;
263 next_update_time = qemu_clock_get_ns(rtc_clock)
264 + NANOSECONDS_PER_SECOND - guest_nsec;
265
266 /* Compute time of next alarm. One second is already accounted
267 * for in next_update_time.
268 */
269 next_alarm_sec = get_next_alarm(s);
270 s->next_alarm_time = next_update_time +
271 (next_alarm_sec - 1) * NANOSECONDS_PER_SECOND;
272
273 /* If update_in_progress latched the UIP bit, we must keep the timer
274 * programmed to the next second, so that UIP is cleared. Otherwise,
275 * if UF is already set, we might be able to optimize.
276 */
277 if (!(s->cmos_data[RTC_REG_A] & REG_A_UIP) &&
278 (s->cmos_data[RTC_REG_C] & REG_C_UF)) {
279 /* If AF cannot change (i.e. either it is set already, or
280 * SET=1 and then the time is not updated), nothing to do.
281 */
282 if ((s->cmos_data[RTC_REG_B] & REG_B_SET) ||
283 (s->cmos_data[RTC_REG_C] & REG_C_AF)) {
284 timer_del(s->update_timer);
285 return;
286 }
287
288 /* UF is set, but AF is clear. Program the timer to target
289 * the alarm time. */
290 next_update_time = s->next_alarm_time;
291 }
292 if (next_update_time != timer_expire_time_ns(s->update_timer)) {
293 timer_mod(s->update_timer, next_update_time);
294 }
295 }
296
297 static inline uint8_t convert_hour(MC146818RtcState *s, uint8_t hour)
298 {
299 if (!(s->cmos_data[RTC_REG_B] & REG_B_24H)) {
300 hour %= 12;
301 if (s->cmos_data[RTC_HOURS] & 0x80) {
302 hour += 12;
303 }
304 }
305 return hour;
306 }
307
308 static uint64_t get_next_alarm(MC146818RtcState *s)
309 {
310 int32_t alarm_sec, alarm_min, alarm_hour, cur_hour, cur_min, cur_sec;
311 int32_t hour, min, sec;
312
313 rtc_update_time(s);
314
315 alarm_sec = rtc_from_bcd(s, s->cmos_data[RTC_SECONDS_ALARM]);
316 alarm_min = rtc_from_bcd(s, s->cmos_data[RTC_MINUTES_ALARM]);
317 alarm_hour = rtc_from_bcd(s, s->cmos_data[RTC_HOURS_ALARM]);
318 alarm_hour = alarm_hour == -1 ? -1 : convert_hour(s, alarm_hour);
319
320 cur_sec = rtc_from_bcd(s, s->cmos_data[RTC_SECONDS]);
321 cur_min = rtc_from_bcd(s, s->cmos_data[RTC_MINUTES]);
322 cur_hour = rtc_from_bcd(s, s->cmos_data[RTC_HOURS]);
323 cur_hour = convert_hour(s, cur_hour);
324
325 if (alarm_hour == -1) {
326 alarm_hour = cur_hour;
327 if (alarm_min == -1) {
328 alarm_min = cur_min;
329 if (alarm_sec == -1) {
330 alarm_sec = cur_sec + 1;
331 } else if (cur_sec > alarm_sec) {
332 alarm_min++;
333 }
334 } else if (cur_min == alarm_min) {
335 if (alarm_sec == -1) {
336 alarm_sec = cur_sec + 1;
337 } else {
338 if (cur_sec > alarm_sec) {
339 alarm_hour++;
340 }
341 }
342 if (alarm_sec == SEC_PER_MIN) {
343 /* wrap to next hour, minutes is not in don't care mode */
344 alarm_sec = 0;
345 alarm_hour++;
346 }
347 } else if (cur_min > alarm_min) {
348 alarm_hour++;
349 }
350 } else if (cur_hour == alarm_hour) {
351 if (alarm_min == -1) {
352 alarm_min = cur_min;
353 if (alarm_sec == -1) {
354 alarm_sec = cur_sec + 1;
355 } else if (cur_sec > alarm_sec) {
356 alarm_min++;
357 }
358
359 if (alarm_sec == SEC_PER_MIN) {
360 alarm_sec = 0;
361 alarm_min++;
362 }
363 /* wrap to next day, hour is not in don't care mode */
364 alarm_min %= MIN_PER_HOUR;
365 } else if (cur_min == alarm_min) {
366 if (alarm_sec == -1) {
367 alarm_sec = cur_sec + 1;
368 }
369 /* wrap to next day, hours+minutes not in don't care mode */
370 alarm_sec %= SEC_PER_MIN;
371 }
372 }
373
374 /* values that are still don't care fire at the next min/sec */
375 if (alarm_min == -1) {
376 alarm_min = 0;
377 }
378 if (alarm_sec == -1) {
379 alarm_sec = 0;
380 }
381
382 /* keep values in range */
383 if (alarm_sec == SEC_PER_MIN) {
384 alarm_sec = 0;
385 alarm_min++;
386 }
387 if (alarm_min == MIN_PER_HOUR) {
388 alarm_min = 0;
389 alarm_hour++;
390 }
391 alarm_hour %= HOUR_PER_DAY;
392
393 hour = alarm_hour - cur_hour;
394 min = hour * MIN_PER_HOUR + alarm_min - cur_min;
395 sec = min * SEC_PER_MIN + alarm_sec - cur_sec;
396 return sec <= 0 ? sec + SEC_PER_DAY : sec;
397 }
398
399 static void rtc_update_timer(void *opaque)
400 {
401 MC146818RtcState *s = opaque;
402 int32_t irqs = REG_C_UF;
403 int32_t new_irqs;
404
405 assert((s->cmos_data[RTC_REG_A] & 0x60) != 0x60);
406
407 /* UIP might have been latched, update time and clear it. */
408 rtc_update_time(s);
409 s->cmos_data[RTC_REG_A] &= ~REG_A_UIP;
410
411 if (qemu_clock_get_ns(rtc_clock) >= s->next_alarm_time) {
412 irqs |= REG_C_AF;
413 if (s->cmos_data[RTC_REG_B] & REG_B_AIE) {
414 qemu_system_wakeup_request(QEMU_WAKEUP_REASON_RTC, NULL);
415 }
416 }
417
418 new_irqs = irqs & ~s->cmos_data[RTC_REG_C];
419 s->cmos_data[RTC_REG_C] |= irqs;
420 if ((new_irqs & s->cmos_data[RTC_REG_B]) != 0) {
421 s->cmos_data[RTC_REG_C] |= REG_C_IRQF;
422 qemu_irq_raise(s->irq);
423 }
424 check_update_timer(s);
425 }
426
427 static void cmos_ioport_write(void *opaque, hwaddr addr,
428 uint64_t data, unsigned size)
429 {
430 MC146818RtcState *s = opaque;
431 uint32_t old_period;
432 bool update_periodic_timer;
433
434 if ((addr & 1) == 0) {
435 s->cmos_index = data & 0x7f;
436 } else {
437 trace_mc146818_rtc_ioport_write(s->cmos_index, data);
438 switch(s->cmos_index) {
439 case RTC_SECONDS_ALARM:
440 case RTC_MINUTES_ALARM:
441 case RTC_HOURS_ALARM:
442 s->cmos_data[s->cmos_index] = data;
443 check_update_timer(s);
444 break;
445 case RTC_IBM_PS2_CENTURY_BYTE:
446 s->cmos_index = RTC_CENTURY;
447 /* fall through */
448 case RTC_CENTURY:
449 case RTC_SECONDS:
450 case RTC_MINUTES:
451 case RTC_HOURS:
452 case RTC_DAY_OF_WEEK:
453 case RTC_DAY_OF_MONTH:
454 case RTC_MONTH:
455 case RTC_YEAR:
456 s->cmos_data[s->cmos_index] = data;
457 /* if in set mode, do not update the time */
458 if (rtc_running(s)) {
459 rtc_set_time(s);
460 check_update_timer(s);
461 }
462 break;
463 case RTC_REG_A:
464 update_periodic_timer = (s->cmos_data[RTC_REG_A] ^ data) & 0x0f;
465 old_period = rtc_periodic_clock_ticks(s);
466
467 if ((data & 0x60) == 0x60) {
468 if (rtc_running(s)) {
469 rtc_update_time(s);
470 }
471 /* What happens to UIP when divider reset is enabled is
472 * unclear from the datasheet. Shouldn't matter much
473 * though.
474 */
475 s->cmos_data[RTC_REG_A] &= ~REG_A_UIP;
476 } else if (((s->cmos_data[RTC_REG_A] & 0x60) == 0x60) &&
477 (data & 0x70) <= 0x20) {
478 /* when the divider reset is removed, the first update cycle
479 * begins one-half second later*/
480 if (!(s->cmos_data[RTC_REG_B] & REG_B_SET)) {
481 s->offset = 500000000;
482 rtc_set_time(s);
483 }
484 s->cmos_data[RTC_REG_A] &= ~REG_A_UIP;
485 }
486 /* UIP bit is read only */
487 s->cmos_data[RTC_REG_A] = (data & ~REG_A_UIP) |
488 (s->cmos_data[RTC_REG_A] & REG_A_UIP);
489
490 if (update_periodic_timer) {
491 periodic_timer_update(s, qemu_clock_get_ns(rtc_clock),
492 old_period, true);
493 }
494
495 check_update_timer(s);
496 break;
497 case RTC_REG_B:
498 update_periodic_timer = (s->cmos_data[RTC_REG_B] ^ data)
499 & REG_B_PIE;
500 old_period = rtc_periodic_clock_ticks(s);
501
502 if (data & REG_B_SET) {
503 /* update cmos to when the rtc was stopping */
504 if (rtc_running(s)) {
505 rtc_update_time(s);
506 }
507 /* set mode: reset UIP mode */
508 s->cmos_data[RTC_REG_A] &= ~REG_A_UIP;
509 data &= ~REG_B_UIE;
510 } else {
511 /* if disabling set mode, update the time */
512 if ((s->cmos_data[RTC_REG_B] & REG_B_SET) &&
513 (s->cmos_data[RTC_REG_A] & 0x70) <= 0x20) {
514 s->offset = get_rtc_ns_since_last_update(s) % NANOSECONDS_PER_SECOND;
515 rtc_set_time(s);
516 }
517 }
518 /* if an interrupt flag is already set when the interrupt
519 * becomes enabled, raise an interrupt immediately. */
520 if (data & s->cmos_data[RTC_REG_C] & REG_C_MASK) {
521 s->cmos_data[RTC_REG_C] |= REG_C_IRQF;
522 qemu_irq_raise(s->irq);
523 } else {
524 s->cmos_data[RTC_REG_C] &= ~REG_C_IRQF;
525 qemu_irq_lower(s->irq);
526 }
527 s->cmos_data[RTC_REG_B] = data;
528
529 if (update_periodic_timer) {
530 periodic_timer_update(s, qemu_clock_get_ns(rtc_clock),
531 old_period, true);
532 }
533
534 check_update_timer(s);
535 break;
536 case RTC_REG_C:
537 case RTC_REG_D:
538 /* cannot write to them */
539 break;
540 default:
541 s->cmos_data[s->cmos_index] = data;
542 break;
543 }
544 }
545 }
546
547 static inline int rtc_to_bcd(MC146818RtcState *s, int a)
548 {
549 if (s->cmos_data[RTC_REG_B] & REG_B_DM) {
550 return a;
551 } else {
552 return ((a / 10) << 4) | (a % 10);
553 }
554 }
555
556 static inline int rtc_from_bcd(MC146818RtcState *s, int a)
557 {
558 if ((a & 0xc0) == 0xc0) {
559 return -1;
560 }
561 if (s->cmos_data[RTC_REG_B] & REG_B_DM) {
562 return a;
563 } else {
564 return ((a >> 4) * 10) + (a & 0x0f);
565 }
566 }
567
568 static void rtc_get_time(MC146818RtcState *s, struct tm *tm)
569 {
570 tm->tm_sec = rtc_from_bcd(s, s->cmos_data[RTC_SECONDS]);
571 tm->tm_min = rtc_from_bcd(s, s->cmos_data[RTC_MINUTES]);
572 tm->tm_hour = rtc_from_bcd(s, s->cmos_data[RTC_HOURS] & 0x7f);
573 if (!(s->cmos_data[RTC_REG_B] & REG_B_24H)) {
574 tm->tm_hour %= 12;
575 if (s->cmos_data[RTC_HOURS] & 0x80) {
576 tm->tm_hour += 12;
577 }
578 }
579 tm->tm_wday = rtc_from_bcd(s, s->cmos_data[RTC_DAY_OF_WEEK]) - 1;
580 tm->tm_mday = rtc_from_bcd(s, s->cmos_data[RTC_DAY_OF_MONTH]);
581 tm->tm_mon = rtc_from_bcd(s, s->cmos_data[RTC_MONTH]) - 1;
582 tm->tm_year =
583 rtc_from_bcd(s, s->cmos_data[RTC_YEAR]) + s->base_year +
584 rtc_from_bcd(s, s->cmos_data[RTC_CENTURY]) * 100 - 1900;
585 }
586
587 static void rtc_set_time(MC146818RtcState *s)
588 {
589 struct tm tm = {};
590 g_autofree const char *qom_path = object_get_canonical_path(OBJECT(s));
591
592 rtc_get_time(s, &tm);
593 s->base_rtc = mktimegm(&tm);
594 s->last_update = qemu_clock_get_ns(rtc_clock);
595
596 qapi_event_send_rtc_change(qemu_timedate_diff(&tm), qom_path);
597 }
598
599 static void rtc_set_cmos(MC146818RtcState *s, const struct tm *tm)
600 {
601 int year;
602
603 s->cmos_data[RTC_SECONDS] = rtc_to_bcd(s, tm->tm_sec);
604 s->cmos_data[RTC_MINUTES] = rtc_to_bcd(s, tm->tm_min);
605 if (s->cmos_data[RTC_REG_B] & REG_B_24H) {
606 /* 24 hour format */
607 s->cmos_data[RTC_HOURS] = rtc_to_bcd(s, tm->tm_hour);
608 } else {
609 /* 12 hour format */
610 int h = (tm->tm_hour % 12) ? tm->tm_hour % 12 : 12;
611 s->cmos_data[RTC_HOURS] = rtc_to_bcd(s, h);
612 if (tm->tm_hour >= 12)
613 s->cmos_data[RTC_HOURS] |= 0x80;
614 }
615 s->cmos_data[RTC_DAY_OF_WEEK] = rtc_to_bcd(s, tm->tm_wday + 1);
616 s->cmos_data[RTC_DAY_OF_MONTH] = rtc_to_bcd(s, tm->tm_mday);
617 s->cmos_data[RTC_MONTH] = rtc_to_bcd(s, tm->tm_mon + 1);
618 year = tm->tm_year + 1900 - s->base_year;
619 s->cmos_data[RTC_YEAR] = rtc_to_bcd(s, year % 100);
620 s->cmos_data[RTC_CENTURY] = rtc_to_bcd(s, year / 100);
621 }
622
623 static void rtc_update_time(MC146818RtcState *s)
624 {
625 struct tm ret;
626 time_t guest_sec;
627
628 guest_sec = s->base_rtc + get_rtc_ns_since_last_update(s) / NANOSECONDS_PER_SECOND;
629 gmtime_r(&guest_sec, &ret);
630
631 /* Is SET flag of Register B disabled? */
632 if ((s->cmos_data[RTC_REG_B] & REG_B_SET) == 0) {
633 rtc_set_cmos(s, &ret);
634 }
635 }
636
637 static int update_in_progress(MC146818RtcState *s)
638 {
639 uint64_t guest_nsec;
640
641 if (!rtc_running(s)) {
642 return 0;
643 }
644 if (timer_pending(s->update_timer)) {
645 int64_t next_update_time = timer_expire_time_ns(s->update_timer);
646 /* Latch UIP until the timer expires. */
647 if (qemu_clock_get_ns(rtc_clock) >=
648 (next_update_time - UIP_HOLD_LENGTH)) {
649 s->cmos_data[RTC_REG_A] |= REG_A_UIP;
650 return 1;
651 }
652 }
653
654 guest_nsec = get_rtc_ns_since_last_update(s);
655 /* UIP bit will be set at last 244us of every second. */
656 if ((guest_nsec % NANOSECONDS_PER_SECOND) >=
657 (NANOSECONDS_PER_SECOND - UIP_HOLD_LENGTH)) {
658 return 1;
659 }
660 return 0;
661 }
662
663 static uint64_t cmos_ioport_read(void *opaque, hwaddr addr,
664 unsigned size)
665 {
666 MC146818RtcState *s = opaque;
667 int ret;
668 if ((addr & 1) == 0) {
669 return 0xff;
670 } else {
671 switch(s->cmos_index) {
672 case RTC_IBM_PS2_CENTURY_BYTE:
673 s->cmos_index = RTC_CENTURY;
674 /* fall through */
675 case RTC_CENTURY:
676 case RTC_SECONDS:
677 case RTC_MINUTES:
678 case RTC_HOURS:
679 case RTC_DAY_OF_WEEK:
680 case RTC_DAY_OF_MONTH:
681 case RTC_MONTH:
682 case RTC_YEAR:
683 /* if not in set mode, calibrate cmos before
684 * reading*/
685 if (rtc_running(s)) {
686 rtc_update_time(s);
687 }
688 ret = s->cmos_data[s->cmos_index];
689 break;
690 case RTC_REG_A:
691 ret = s->cmos_data[s->cmos_index];
692 if (update_in_progress(s)) {
693 ret |= REG_A_UIP;
694 }
695 break;
696 case RTC_REG_C:
697 ret = s->cmos_data[s->cmos_index];
698 qemu_irq_lower(s->irq);
699 s->cmos_data[RTC_REG_C] = 0x00;
700 if (ret & (REG_C_UF | REG_C_AF)) {
701 check_update_timer(s);
702 }
703
704 if(s->irq_coalesced &&
705 (s->cmos_data[RTC_REG_B] & REG_B_PIE) &&
706 s->irq_reinject_on_ack_count < RTC_REINJECT_ON_ACK_COUNT) {
707 s->irq_reinject_on_ack_count++;
708 s->cmos_data[RTC_REG_C] |= REG_C_IRQF | REG_C_PF;
709 DPRINTF_C("cmos: injecting on ack\n");
710 if (rtc_policy_slew_deliver_irq(s)) {
711 s->irq_coalesced--;
712 DPRINTF_C("cmos: coalesced irqs decreased to %d\n",
713 s->irq_coalesced);
714 }
715 }
716 break;
717 default:
718 ret = s->cmos_data[s->cmos_index];
719 break;
720 }
721 trace_mc146818_rtc_ioport_read(s->cmos_index, ret);
722 return ret;
723 }
724 }
725
726 void mc146818rtc_set_cmos_data(MC146818RtcState *s, int addr, int val)
727 {
728 assert(addr >= 0 && addr < ARRAY_SIZE(s->cmos_data));
729 s->cmos_data[addr] = val;
730 }
731
732 int mc146818rtc_get_cmos_data(MC146818RtcState *s, int addr)
733 {
734 assert(addr >= 0 && addr < ARRAY_SIZE(s->cmos_data));
735 return s->cmos_data[addr];
736 }
737
738 static void rtc_set_date_from_host(ISADevice *dev)
739 {
740 MC146818RtcState *s = MC146818_RTC(dev);
741 struct tm tm;
742
743 qemu_get_timedate(&tm, 0);
744
745 s->base_rtc = mktimegm(&tm);
746 s->last_update = qemu_clock_get_ns(rtc_clock);
747 s->offset = 0;
748
749 /* set the CMOS date */
750 rtc_set_cmos(s, &tm);
751 }
752
753 static int rtc_pre_save(void *opaque)
754 {
755 MC146818RtcState *s = opaque;
756
757 rtc_update_time(s);
758
759 return 0;
760 }
761
762 static int rtc_post_load(void *opaque, int version_id)
763 {
764 MC146818RtcState *s = opaque;
765
766 if (version_id <= 2 || rtc_clock == QEMU_CLOCK_REALTIME) {
767 rtc_set_time(s);
768 s->offset = 0;
769 check_update_timer(s);
770 }
771 s->period = rtc_periodic_clock_ticks(s);
772
773 /* The periodic timer is deterministic in record/replay mode,
774 * so there is no need to update it after loading the vmstate.
775 * Reading RTC here would misalign record and replay.
776 */
777 if (replay_mode == REPLAY_MODE_NONE) {
778 uint64_t now = qemu_clock_get_ns(rtc_clock);
779 if (now < s->next_periodic_time ||
780 now > (s->next_periodic_time + get_max_clock_jump())) {
781 periodic_timer_update(s, qemu_clock_get_ns(rtc_clock), s->period, false);
782 }
783 }
784
785 if (version_id >= 2) {
786 if (s->lost_tick_policy == LOST_TICK_POLICY_SLEW) {
787 rtc_coalesced_timer_update(s);
788 }
789 }
790 return 0;
791 }
792
793 static bool rtc_irq_reinject_on_ack_count_needed(void *opaque)
794 {
795 MC146818RtcState *s = (MC146818RtcState *)opaque;
796 return s->irq_reinject_on_ack_count != 0;
797 }
798
799 static const VMStateDescription vmstate_rtc_irq_reinject_on_ack_count = {
800 .name = "mc146818rtc/irq_reinject_on_ack_count",
801 .version_id = 1,
802 .minimum_version_id = 1,
803 .needed = rtc_irq_reinject_on_ack_count_needed,
804 .fields = (const VMStateField[]) {
805 VMSTATE_UINT16(irq_reinject_on_ack_count, MC146818RtcState),
806 VMSTATE_END_OF_LIST()
807 }
808 };
809
810 static const VMStateDescription vmstate_rtc = {
811 .name = "mc146818rtc",
812 .version_id = 3,
813 .minimum_version_id = 3,
814 .pre_save = rtc_pre_save,
815 .post_load = rtc_post_load,
816 .fields = (const VMStateField[]) {
817 VMSTATE_BUFFER(cmos_data, MC146818RtcState),
818 VMSTATE_UINT8(cmos_index, MC146818RtcState),
819 VMSTATE_UNUSED(7*4),
820 VMSTATE_TIMER_PTR(periodic_timer, MC146818RtcState),
821 VMSTATE_INT64(next_periodic_time, MC146818RtcState),
822 VMSTATE_UNUSED(3*8),
823 VMSTATE_UINT32(irq_coalesced, MC146818RtcState),
824 VMSTATE_UINT32(period, MC146818RtcState),
825 VMSTATE_UINT64(base_rtc, MC146818RtcState),
826 VMSTATE_UINT64(last_update, MC146818RtcState),
827 VMSTATE_INT64(offset, MC146818RtcState),
828 VMSTATE_TIMER_PTR(update_timer, MC146818RtcState),
829 VMSTATE_UINT64(next_alarm_time, MC146818RtcState),
830 VMSTATE_END_OF_LIST()
831 },
832 .subsections = (const VMStateDescription * const []) {
833 &vmstate_rtc_irq_reinject_on_ack_count,
834 NULL
835 }
836 };
837
838 /* set CMOS shutdown status register (index 0xF) as S3_resume(0xFE)
839 BIOS will read it and start S3 resume at POST Entry */
840 static void rtc_notify_suspend(Notifier *notifier, void *data)
841 {
842 MC146818RtcState *s = container_of(notifier, MC146818RtcState,
843 suspend_notifier);
844 mc146818rtc_set_cmos_data(s, 0xF, 0xFE);
845 }
846
847 static const MemoryRegionOps cmos_ops = {
848 .read = cmos_ioport_read,
849 .write = cmos_ioport_write,
850 .impl = {
851 .min_access_size = 1,
852 .max_access_size = 1,
853 },
854 .endianness = DEVICE_LITTLE_ENDIAN,
855 };
856
857 static void rtc_get_date(Object *obj, struct tm *current_tm, Error **errp)
858 {
859 MC146818RtcState *s = MC146818_RTC(obj);
860
861 rtc_update_time(s);
862 rtc_get_time(s, current_tm);
863 }
864
865 static void rtc_realizefn(DeviceState *dev, Error **errp)
866 {
867 ISADevice *isadev = ISA_DEVICE(dev);
868 MC146818RtcState *s = MC146818_RTC(dev);
869
870 s->cmos_data[RTC_REG_A] = 0x26;
871 s->cmos_data[RTC_REG_B] = 0x02;
872 s->cmos_data[RTC_REG_C] = 0x00;
873 s->cmos_data[RTC_REG_D] = 0x80;
874
875 /* This is for historical reasons. The default base year qdev property
876 * was set to 2000 for most machine types before the century byte was
877 * implemented.
878 *
879 * This if statement means that the century byte will be always 0
880 * (at least until 2079...) for base_year = 1980, but will be set
881 * correctly for base_year = 2000.
882 */
883 if (s->base_year == 2000) {
884 s->base_year = 0;
885 }
886
887 if (s->isairq >= ISA_NUM_IRQS) {
888 error_setg(errp, "Maximum value for \"irq\" is: %u", ISA_NUM_IRQS - 1);
889 return;
890 }
891
892 rtc_set_date_from_host(isadev);
893
894 switch (s->lost_tick_policy) {
895 case LOST_TICK_POLICY_SLEW:
896 s->coalesced_timer =
897 timer_new_ns(rtc_clock, rtc_coalesced_timer, s);
898 break;
899 case LOST_TICK_POLICY_DISCARD:
900 break;
901 default:
902 error_setg(errp, "Invalid lost tick policy.");
903 return;
904 }
905
906 s->periodic_timer = timer_new_ns(rtc_clock, rtc_periodic_timer, s);
907 s->update_timer = timer_new_ns(rtc_clock, rtc_update_timer, s);
908 check_update_timer(s);
909
910 s->suspend_notifier.notify = rtc_notify_suspend;
911 qemu_register_suspend_notifier(&s->suspend_notifier);
912
913 memory_region_init_io(&s->io, OBJECT(s), &cmos_ops, s, "rtc", 2);
914 isa_register_ioport(isadev, &s->io, s->io_base);
915
916 /* register rtc 0x70 port for coalesced_pio */
917 memory_region_set_flush_coalesced(&s->io);
918 memory_region_init_io(&s->coalesced_io, OBJECT(s), &cmos_ops,
919 s, "rtc-index", 1);
920 memory_region_add_subregion(&s->io, 0, &s->coalesced_io);
921 memory_region_add_coalescing(&s->coalesced_io, 0, 1);
922
923 qdev_init_gpio_out(dev, &s->irq, 1);
924 }
925
926 MC146818RtcState *mc146818_rtc_init(ISABus *bus, int base_year,
927 qemu_irq intercept_irq)
928 {
929 DeviceState *dev;
930 ISADevice *isadev;
931 MC146818RtcState *s;
932
933 isadev = isa_new(TYPE_MC146818_RTC);
934 dev = DEVICE(isadev);
935 s = MC146818_RTC(isadev);
936 qdev_prop_set_int32(dev, "base_year", base_year);
937 isa_realize_and_unref(isadev, bus, &error_fatal);
938 if (intercept_irq) {
939 qdev_connect_gpio_out(dev, 0, intercept_irq);
940 } else {
941 isa_connect_gpio_out(isadev, 0, s->isairq);
942 }
943
944 object_property_add_alias(qdev_get_machine(), "rtc-time", OBJECT(isadev),
945 "date");
946
947 return s;
948 }
949
950 static const Property mc146818rtc_properties[] = {
951 DEFINE_PROP_INT32("base_year", MC146818RtcState, base_year, 1980),
952 DEFINE_PROP_UINT16("iobase", MC146818RtcState, io_base, RTC_ISA_BASE),
953 DEFINE_PROP_UINT8("irq", MC146818RtcState, isairq, RTC_ISA_IRQ),
954 DEFINE_PROP_LOSTTICKPOLICY("lost_tick_policy", MC146818RtcState,
955 lost_tick_policy, LOST_TICK_POLICY_DISCARD),
956 };
957
958 static void rtc_reset_enter(Object *obj, ResetType type)
959 {
960 MC146818RtcState *s = MC146818_RTC(obj);
961
962 /* Reason: VM do suspend self will set 0xfe
963 * Reset any values other than 0xfe(Guest suspend case) */
964 if (s->cmos_data[0x0f] != 0xfe) {
965 s->cmos_data[0x0f] = 0x00;
966 }
967
968 s->cmos_data[RTC_REG_B] &= ~(REG_B_PIE | REG_B_AIE | REG_B_SQWE);
969 s->cmos_data[RTC_REG_C] &= ~(REG_C_UF | REG_C_IRQF | REG_C_PF | REG_C_AF);
970 check_update_timer(s);
971
972
973 if (s->lost_tick_policy == LOST_TICK_POLICY_SLEW) {
974 s->irq_coalesced = 0;
975 s->irq_reinject_on_ack_count = 0;
976 }
977 }
978
979 static void rtc_reset_hold(Object *obj, ResetType type)
980 {
981 MC146818RtcState *s = MC146818_RTC(obj);
982
983 qemu_irq_lower(s->irq);
984 }
985
986 static void rtc_build_aml(AcpiDevAmlIf *adev, Aml *scope)
987 {
988 MC146818RtcState *s = MC146818_RTC(adev);
989 Aml *dev;
990 Aml *crs;
991
992 /*
993 * Reserving 8 io ports here, following what physical hardware
994 * does, even though qemu only responds to the first two ports.
995 */
996 crs = aml_resource_template();
997 aml_append(crs, aml_io(AML_DECODE16, s->io_base, s->io_base,
998 0x01, 0x08));
999 aml_append(crs, aml_irq_no_flags(s->isairq));
1000
1001 dev = aml_device("RTC");
1002 aml_append(dev, aml_name_decl("_HID", aml_eisaid("PNP0B00")));
1003 aml_append(dev, aml_name_decl("_CRS", crs));
1004
1005 aml_append(scope, dev);
1006 }
1007
1008 static void rtc_class_initfn(ObjectClass *klass, const void *data)
1009 {
1010 DeviceClass *dc = DEVICE_CLASS(klass);
1011 ResettableClass *rc = RESETTABLE_CLASS(klass);
1012 AcpiDevAmlIfClass *adevc = ACPI_DEV_AML_IF_CLASS(klass);
1013
1014 dc->realize = rtc_realizefn;
1015 dc->vmsd = &vmstate_rtc;
1016 rc->phases.enter = rtc_reset_enter;
1017 rc->phases.hold = rtc_reset_hold;
1018 adevc->build_dev_aml = rtc_build_aml;
1019 device_class_set_props(dc, mc146818rtc_properties);
1020 set_bit(DEVICE_CATEGORY_MISC, dc->categories);
1021
1022 object_class_property_add_tm(klass, "date", rtc_get_date);
1023 }
1024
1025 static const TypeInfo mc146818rtc_info = {
1026 .name = TYPE_MC146818_RTC,
1027 .parent = TYPE_ISA_DEVICE,
1028 .instance_size = sizeof(MC146818RtcState),
1029 .class_init = rtc_class_initfn,
1030 .interfaces = (const InterfaceInfo[]) {
1031 { TYPE_ACPI_DEV_AML_IF },
1032 { },
1033 },
1034 };
1035
1036 static void mc146818rtc_register_types(void)
1037 {
1038 type_register_static(&mc146818rtc_info);
1039 }
1040
1041 type_init(mc146818rtc_register_types)