xref: /openbmc/qemu/tests/qtest/rtc-test.c (revision 4921d0a7)
1 /*
2  * QTest testcase for the MC146818 real-time clock
3  *
4  * Copyright IBM, Corp. 2012
5  *
6  * Authors:
7  *  Anthony Liguori   <aliguori@us.ibm.com>
8  *
9  * This work is licensed under the terms of the GNU GPL, version 2 or later.
10  * See the COPYING file in the top-level directory.
11  *
12  */
13 
14 #include "qemu/osdep.h"
15 
16 #include "libqtest-single.h"
17 #include "qemu/timer.h"
18 #include "hw/rtc/mc146818rtc.h"
19 #include "hw/rtc/mc146818rtc_regs.h"
20 
21 #define UIP_HOLD_LENGTH           (8 * NANOSECONDS_PER_SECOND / 32768)
22 
23 static uint8_t base = 0x70;
24 
25 static int bcd2dec(int value)
26 {
27     return (((value >> 4) & 0x0F) * 10) + (value & 0x0F);
28 }
29 
30 static uint8_t cmos_read(uint8_t reg)
31 {
32     outb(base + 0, reg);
33     return inb(base + 1);
34 }
35 
36 static void cmos_write(uint8_t reg, uint8_t val)
37 {
38     outb(base + 0, reg);
39     outb(base + 1, val);
40 }
41 
42 static int tm_cmp(struct tm *lhs, struct tm *rhs)
43 {
44     time_t a, b;
45     struct tm d1, d2;
46 
47     memcpy(&d1, lhs, sizeof(d1));
48     memcpy(&d2, rhs, sizeof(d2));
49 
50     a = mktime(&d1);
51     b = mktime(&d2);
52 
53     if (a < b) {
54         return -1;
55     } else if (a > b) {
56         return 1;
57     }
58 
59     return 0;
60 }
61 
62 #if 0
63 static void print_tm(struct tm *tm)
64 {
65     printf("%04d-%02d-%02d %02d:%02d:%02d\n",
66            tm->tm_year + 1900, tm->tm_mon + 1, tm->tm_mday,
67            tm->tm_hour, tm->tm_min, tm->tm_sec, tm->tm_gmtoff);
68 }
69 #endif
70 
71 static void cmos_get_date_time(struct tm *date)
72 {
73     int base_year = 2000, hour_offset;
74     int sec, min, hour, mday, mon, year;
75     time_t ts;
76     struct tm dummy;
77 
78     sec = cmos_read(RTC_SECONDS);
79     min = cmos_read(RTC_MINUTES);
80     hour = cmos_read(RTC_HOURS);
81     mday = cmos_read(RTC_DAY_OF_MONTH);
82     mon = cmos_read(RTC_MONTH);
83     year = cmos_read(RTC_YEAR);
84 
85     if ((cmos_read(RTC_REG_B) & REG_B_DM) == 0) {
86         sec = bcd2dec(sec);
87         min = bcd2dec(min);
88         hour = bcd2dec(hour);
89         mday = bcd2dec(mday);
90         mon = bcd2dec(mon);
91         year = bcd2dec(year);
92         hour_offset = 80;
93     } else {
94         hour_offset = 0x80;
95     }
96 
97     if ((cmos_read(0x0B) & REG_B_24H) == 0) {
98         if (hour >= hour_offset) {
99             hour -= hour_offset;
100             hour += 12;
101         }
102     }
103 
104     ts = time(NULL);
105     localtime_r(&ts, &dummy);
106 
107     date->tm_isdst = dummy.tm_isdst;
108     date->tm_sec = sec;
109     date->tm_min = min;
110     date->tm_hour = hour;
111     date->tm_mday = mday;
112     date->tm_mon = mon - 1;
113     date->tm_year = base_year + year - 1900;
114 #if !defined(__sun__) && !defined(_WIN32)
115     date->tm_gmtoff = 0;
116 #endif
117 
118     ts = mktime(date);
119 }
120 
121 static void check_time(int wiggle)
122 {
123     struct tm start, date[4], end;
124     struct tm *datep;
125     time_t ts;
126 
127     /*
128      * This check assumes a few things.  First, we cannot guarantee that we get
129      * a consistent reading from the wall clock because we may hit an edge of
130      * the clock while reading.  To work around this, we read four clock readings
131      * such that at least two of them should match.  We need to assume that one
132      * reading is corrupt so we need four readings to ensure that we have at
133      * least two consecutive identical readings
134      *
135      * It's also possible that we'll cross an edge reading the host clock so
136      * simply check to make sure that the clock reading is within the period of
137      * when we expect it to be.
138      */
139 
140     ts = time(NULL);
141     gmtime_r(&ts, &start);
142 
143     cmos_get_date_time(&date[0]);
144     cmos_get_date_time(&date[1]);
145     cmos_get_date_time(&date[2]);
146     cmos_get_date_time(&date[3]);
147 
148     ts = time(NULL);
149     gmtime_r(&ts, &end);
150 
151     if (tm_cmp(&date[0], &date[1]) == 0) {
152         datep = &date[0];
153     } else if (tm_cmp(&date[1], &date[2]) == 0) {
154         datep = &date[1];
155     } else if (tm_cmp(&date[2], &date[3]) == 0) {
156         datep = &date[2];
157     } else {
158         g_assert_not_reached();
159     }
160 
161     if (!(tm_cmp(&start, datep) <= 0 && tm_cmp(datep, &end) <= 0)) {
162         long t, s;
163 
164         start.tm_isdst = datep->tm_isdst;
165 
166         t = (long)mktime(datep);
167         s = (long)mktime(&start);
168         if (t < s) {
169             g_test_message("RTC is %ld second(s) behind wall-clock", (s - t));
170         } else {
171             g_test_message("RTC is %ld second(s) ahead of wall-clock", (t - s));
172         }
173 
174         g_assert_cmpint(ABS(t - s), <=, wiggle);
175     }
176 }
177 
178 static int wiggle = 2;
179 
180 static void set_year_20xx(void)
181 {
182     /* Set BCD mode */
183     cmos_write(RTC_REG_B, REG_B_24H);
184     cmos_write(RTC_REG_A, 0x76);
185     cmos_write(RTC_YEAR, 0x11);
186     cmos_write(RTC_CENTURY, 0x20);
187     cmos_write(RTC_MONTH, 0x02);
188     cmos_write(RTC_DAY_OF_MONTH, 0x02);
189     cmos_write(RTC_HOURS, 0x02);
190     cmos_write(RTC_MINUTES, 0x04);
191     cmos_write(RTC_SECONDS, 0x58);
192     cmos_write(RTC_REG_A, 0x26);
193 
194     g_assert_cmpint(cmos_read(RTC_HOURS), ==, 0x02);
195     g_assert_cmpint(cmos_read(RTC_MINUTES), ==, 0x04);
196     g_assert_cmpint(cmos_read(RTC_SECONDS), >=, 0x58);
197     g_assert_cmpint(cmos_read(RTC_DAY_OF_MONTH), ==, 0x02);
198     g_assert_cmpint(cmos_read(RTC_MONTH), ==, 0x02);
199     g_assert_cmpint(cmos_read(RTC_YEAR), ==, 0x11);
200     g_assert_cmpint(cmos_read(RTC_CENTURY), ==, 0x20);
201 
202     if (sizeof(time_t) == 4) {
203         return;
204     }
205 
206     /* Set a date in 2080 to ensure there is no year-2038 overflow.  */
207     cmos_write(RTC_REG_A, 0x76);
208     cmos_write(RTC_YEAR, 0x80);
209     cmos_write(RTC_REG_A, 0x26);
210 
211     g_assert_cmpint(cmos_read(RTC_HOURS), ==, 0x02);
212     g_assert_cmpint(cmos_read(RTC_MINUTES), ==, 0x04);
213     g_assert_cmpint(cmos_read(RTC_SECONDS), >=, 0x58);
214     g_assert_cmpint(cmos_read(RTC_DAY_OF_MONTH), ==, 0x02);
215     g_assert_cmpint(cmos_read(RTC_MONTH), ==, 0x02);
216     g_assert_cmpint(cmos_read(RTC_YEAR), ==, 0x80);
217     g_assert_cmpint(cmos_read(RTC_CENTURY), ==, 0x20);
218 
219     cmos_write(RTC_REG_A, 0x76);
220     cmos_write(RTC_YEAR, 0x11);
221     cmos_write(RTC_REG_A, 0x26);
222 
223     g_assert_cmpint(cmos_read(RTC_HOURS), ==, 0x02);
224     g_assert_cmpint(cmos_read(RTC_MINUTES), ==, 0x04);
225     g_assert_cmpint(cmos_read(RTC_SECONDS), >=, 0x58);
226     g_assert_cmpint(cmos_read(RTC_DAY_OF_MONTH), ==, 0x02);
227     g_assert_cmpint(cmos_read(RTC_MONTH), ==, 0x02);
228     g_assert_cmpint(cmos_read(RTC_YEAR), ==, 0x11);
229     g_assert_cmpint(cmos_read(RTC_CENTURY), ==, 0x20);
230 }
231 
232 static void set_year_1980(void)
233 {
234     /* Set BCD mode */
235     cmos_write(RTC_REG_B, REG_B_24H);
236     cmos_write(RTC_REG_A, 0x76);
237     cmos_write(RTC_YEAR, 0x80);
238     cmos_write(RTC_CENTURY, 0x19);
239     cmos_write(RTC_MONTH, 0x02);
240     cmos_write(RTC_DAY_OF_MONTH, 0x02);
241     cmos_write(RTC_HOURS, 0x02);
242     cmos_write(RTC_MINUTES, 0x04);
243     cmos_write(RTC_SECONDS, 0x58);
244     cmos_write(RTC_REG_A, 0x26);
245 
246     g_assert_cmpint(cmos_read(RTC_HOURS), ==, 0x02);
247     g_assert_cmpint(cmos_read(RTC_MINUTES), ==, 0x04);
248     g_assert_cmpint(cmos_read(RTC_SECONDS), >=, 0x58);
249     g_assert_cmpint(cmos_read(RTC_DAY_OF_MONTH), ==, 0x02);
250     g_assert_cmpint(cmos_read(RTC_MONTH), ==, 0x02);
251     g_assert_cmpint(cmos_read(RTC_YEAR), ==, 0x80);
252     g_assert_cmpint(cmos_read(RTC_CENTURY), ==, 0x19);
253 }
254 
255 static void bcd_check_time(void)
256 {
257     /* Set BCD mode */
258     cmos_write(RTC_REG_B, REG_B_24H);
259     check_time(wiggle);
260 }
261 
262 static void dec_check_time(void)
263 {
264     /* Set DEC mode */
265     cmos_write(RTC_REG_B, REG_B_24H | REG_B_DM);
266     check_time(wiggle);
267 }
268 
269 static void alarm_time(void)
270 {
271     struct tm now;
272     time_t ts;
273     int i;
274 
275     ts = time(NULL);
276     gmtime_r(&ts, &now);
277 
278     /* set DEC mode */
279     cmos_write(RTC_REG_B, REG_B_24H | REG_B_DM);
280 
281     g_assert(!get_irq(RTC_ISA_IRQ));
282     cmos_read(RTC_REG_C);
283 
284     now.tm_sec = (now.tm_sec + 2) % 60;
285     cmos_write(RTC_SECONDS_ALARM, now.tm_sec);
286     cmos_write(RTC_MINUTES_ALARM, RTC_ALARM_DONT_CARE);
287     cmos_write(RTC_HOURS_ALARM, RTC_ALARM_DONT_CARE);
288     cmos_write(RTC_REG_B, cmos_read(RTC_REG_B) | REG_B_AIE);
289 
290     for (i = 0; i < 2 + wiggle; i++) {
291         if (get_irq(RTC_ISA_IRQ)) {
292             break;
293         }
294 
295         clock_step(NANOSECONDS_PER_SECOND);
296     }
297 
298     g_assert(get_irq(RTC_ISA_IRQ));
299     g_assert((cmos_read(RTC_REG_C) & REG_C_AF) != 0);
300     g_assert(cmos_read(RTC_REG_C) == 0);
301 }
302 
303 static void set_time_regs(int h, int m, int s)
304 {
305     cmos_write(RTC_HOURS, h);
306     cmos_write(RTC_MINUTES, m);
307     cmos_write(RTC_SECONDS, s);
308 }
309 
310 static void set_time(int mode, int h, int m, int s)
311 {
312     cmos_write(RTC_REG_B, mode);
313     cmos_write(RTC_REG_A, 0x76);
314     set_time_regs(h, m, s);
315     cmos_write(RTC_REG_A, 0x26);
316 }
317 
318 static void set_datetime_bcd(int h, int min, int s, int d, int m, int y)
319 {
320     cmos_write(RTC_HOURS, h);
321     cmos_write(RTC_MINUTES, min);
322     cmos_write(RTC_SECONDS, s);
323     cmos_write(RTC_YEAR, y & 0xFF);
324     cmos_write(RTC_CENTURY, y >> 8);
325     cmos_write(RTC_MONTH, m);
326     cmos_write(RTC_DAY_OF_MONTH, d);
327 }
328 
329 static void set_datetime_dec(int h, int min, int s, int d, int m, int y)
330 {
331     cmos_write(RTC_HOURS, h);
332     cmos_write(RTC_MINUTES, min);
333     cmos_write(RTC_SECONDS, s);
334     cmos_write(RTC_YEAR, y % 100);
335     cmos_write(RTC_CENTURY, y / 100);
336     cmos_write(RTC_MONTH, m);
337     cmos_write(RTC_DAY_OF_MONTH, d);
338 }
339 
340 static void set_datetime(int mode, int h, int min, int s, int d, int m, int y)
341 {
342     cmos_write(RTC_REG_B, mode);
343 
344     cmos_write(RTC_REG_A, 0x76);
345     if (mode & REG_B_DM) {
346         set_datetime_dec(h, min, s, d, m, y);
347     } else {
348         set_datetime_bcd(h, min, s, d, m, y);
349     }
350     cmos_write(RTC_REG_A, 0x26);
351 }
352 
353 #define assert_time(h, m, s) \
354     do { \
355         g_assert_cmpint(cmos_read(RTC_HOURS), ==, h); \
356         g_assert_cmpint(cmos_read(RTC_MINUTES), ==, m); \
357         g_assert_cmpint(cmos_read(RTC_SECONDS), ==, s); \
358     } while(0)
359 
360 #define assert_datetime_bcd(h, min, s, d, m, y) \
361     do { \
362         g_assert_cmpint(cmos_read(RTC_HOURS), ==, h); \
363         g_assert_cmpint(cmos_read(RTC_MINUTES), ==, min); \
364         g_assert_cmpint(cmos_read(RTC_SECONDS), ==, s); \
365         g_assert_cmpint(cmos_read(RTC_DAY_OF_MONTH), ==, d); \
366         g_assert_cmpint(cmos_read(RTC_MONTH), ==, m); \
367         g_assert_cmpint(cmos_read(RTC_YEAR), ==, (y & 0xFF)); \
368         g_assert_cmpint(cmos_read(RTC_CENTURY), ==, (y >> 8)); \
369     } while(0)
370 
371 static void basic_12h_bcd(void)
372 {
373     /* set BCD 12 hour mode */
374     set_time(0, 0x81, 0x59, 0x00);
375     clock_step(1000000000LL);
376     assert_time(0x81, 0x59, 0x01);
377     clock_step(59000000000LL);
378     assert_time(0x82, 0x00, 0x00);
379 
380     /* test BCD wraparound */
381     set_time(0, 0x09, 0x59, 0x59);
382     clock_step(60000000000LL);
383     assert_time(0x10, 0x00, 0x59);
384 
385     /* 12 AM -> 1 AM */
386     set_time(0, 0x12, 0x59, 0x59);
387     clock_step(1000000000LL);
388     assert_time(0x01, 0x00, 0x00);
389 
390     /* 12 PM -> 1 PM */
391     set_time(0, 0x92, 0x59, 0x59);
392     clock_step(1000000000LL);
393     assert_time(0x81, 0x00, 0x00);
394 
395     /* 11 AM -> 12 PM */
396     set_time(0, 0x11, 0x59, 0x59);
397     clock_step(1000000000LL);
398     assert_time(0x92, 0x00, 0x00);
399     /* TODO: test day wraparound */
400 
401     /* 11 PM -> 12 AM */
402     set_time(0, 0x91, 0x59, 0x59);
403     clock_step(1000000000LL);
404     assert_time(0x12, 0x00, 0x00);
405     /* TODO: test day wraparound */
406 }
407 
408 static void basic_12h_dec(void)
409 {
410     /* set decimal 12 hour mode */
411     set_time(REG_B_DM, 0x81, 59, 0);
412     clock_step(1000000000LL);
413     assert_time(0x81, 59, 1);
414     clock_step(59000000000LL);
415     assert_time(0x82, 0, 0);
416 
417     /* 12 PM -> 1 PM */
418     set_time(REG_B_DM, 0x8c, 59, 59);
419     clock_step(1000000000LL);
420     assert_time(0x81, 0, 0);
421 
422     /* 12 AM -> 1 AM */
423     set_time(REG_B_DM, 0x0c, 59, 59);
424     clock_step(1000000000LL);
425     assert_time(0x01, 0, 0);
426 
427     /* 11 AM -> 12 PM */
428     set_time(REG_B_DM, 0x0b, 59, 59);
429     clock_step(1000000000LL);
430     assert_time(0x8c, 0, 0);
431 
432     /* 11 PM -> 12 AM */
433     set_time(REG_B_DM, 0x8b, 59, 59);
434     clock_step(1000000000LL);
435     assert_time(0x0c, 0, 0);
436     /* TODO: test day wraparound */
437 }
438 
439 static void basic_24h_bcd(void)
440 {
441     /* set BCD 24 hour mode */
442     set_time(REG_B_24H, 0x09, 0x59, 0x00);
443     clock_step(1000000000LL);
444     assert_time(0x09, 0x59, 0x01);
445     clock_step(59000000000LL);
446     assert_time(0x10, 0x00, 0x00);
447 
448     /* test BCD wraparound */
449     set_time(REG_B_24H, 0x09, 0x59, 0x00);
450     clock_step(60000000000LL);
451     assert_time(0x10, 0x00, 0x00);
452 
453     /* TODO: test day wraparound */
454     set_time(REG_B_24H, 0x23, 0x59, 0x00);
455     clock_step(60000000000LL);
456     assert_time(0x00, 0x00, 0x00);
457 }
458 
459 static void basic_24h_dec(void)
460 {
461     /* set decimal 24 hour mode */
462     set_time(REG_B_24H | REG_B_DM, 9, 59, 0);
463     clock_step(1000000000LL);
464     assert_time(9, 59, 1);
465     clock_step(59000000000LL);
466     assert_time(10, 0, 0);
467 
468     /* test BCD wraparound */
469     set_time(REG_B_24H | REG_B_DM, 9, 59, 0);
470     clock_step(60000000000LL);
471     assert_time(10, 0, 0);
472 
473     /* TODO: test day wraparound */
474     set_time(REG_B_24H | REG_B_DM, 23, 59, 0);
475     clock_step(60000000000LL);
476     assert_time(0, 0, 0);
477 }
478 
479 static void am_pm_alarm(void)
480 {
481     cmos_write(RTC_MINUTES_ALARM, 0xC0);
482     cmos_write(RTC_SECONDS_ALARM, 0xC0);
483 
484     /* set BCD 12 hour mode */
485     cmos_write(RTC_REG_B, 0);
486 
487     /* Set time and alarm hour.  */
488     cmos_write(RTC_REG_A, 0x76);
489     cmos_write(RTC_HOURS_ALARM, 0x82);
490     cmos_write(RTC_HOURS, 0x81);
491     cmos_write(RTC_MINUTES, 0x59);
492     cmos_write(RTC_SECONDS, 0x00);
493     cmos_read(RTC_REG_C);
494     cmos_write(RTC_REG_A, 0x26);
495 
496     /* Check that alarm triggers when AM/PM is set.  */
497     clock_step(60000000000LL);
498     g_assert(cmos_read(RTC_HOURS) == 0x82);
499     g_assert((cmos_read(RTC_REG_C) & REG_C_AF) != 0);
500 
501     /*
502      * Each of the following two tests takes over 60 seconds due to the time
503      * needed to report the PIT interrupts.  Unfortunately, our PIT device
504      * model keeps counting even when GATE=0, so we cannot simply disable
505      * it in main().
506      */
507     if (g_test_quick()) {
508         return;
509     }
510 
511     /* set DEC 12 hour mode */
512     cmos_write(RTC_REG_B, REG_B_DM);
513 
514     /* Set time and alarm hour.  */
515     cmos_write(RTC_REG_A, 0x76);
516     cmos_write(RTC_HOURS_ALARM, 0x82);
517     cmos_write(RTC_HOURS, 3);
518     cmos_write(RTC_MINUTES, 0);
519     cmos_write(RTC_SECONDS, 0);
520     cmos_read(RTC_REG_C);
521     cmos_write(RTC_REG_A, 0x26);
522 
523     /* Check that alarm triggers.  */
524     clock_step(3600 * 11 * 1000000000LL);
525     g_assert(cmos_read(RTC_HOURS) == 0x82);
526     g_assert((cmos_read(RTC_REG_C) & REG_C_AF) != 0);
527 
528     /* Same as above, with inverted HOURS and HOURS_ALARM.  */
529     cmos_write(RTC_REG_A, 0x76);
530     cmos_write(RTC_HOURS_ALARM, 2);
531     cmos_write(RTC_HOURS, 3);
532     cmos_write(RTC_MINUTES, 0);
533     cmos_write(RTC_SECONDS, 0);
534     cmos_read(RTC_REG_C);
535     cmos_write(RTC_REG_A, 0x26);
536 
537     /* Check that alarm does not trigger if hours differ only by AM/PM.  */
538     clock_step(3600 * 11 * 1000000000LL);
539     g_assert(cmos_read(RTC_HOURS) == 0x82);
540     g_assert((cmos_read(RTC_REG_C) & REG_C_AF) == 0);
541 }
542 
543 /* success if no crash or abort */
544 static void fuzz_registers(void)
545 {
546     unsigned int i;
547 
548     for (i = 0; i < 1000; i++) {
549         uint8_t reg, val;
550 
551         reg = (uint8_t)g_test_rand_int_range(0, 16);
552         val = (uint8_t)g_test_rand_int_range(0, 256);
553 
554         cmos_write(reg, val);
555         cmos_read(reg);
556     }
557 }
558 
559 static void register_b_set_flag(void)
560 {
561     if (cmos_read(RTC_REG_A) & REG_A_UIP) {
562         clock_step(UIP_HOLD_LENGTH + NANOSECONDS_PER_SECOND / 5);
563     }
564     g_assert_cmpint(cmos_read(RTC_REG_A) & REG_A_UIP, ==, 0);
565 
566     /* Enable binary-coded decimal (BCD) mode and SET flag in Register B*/
567     cmos_write(RTC_REG_B, REG_B_24H | REG_B_SET);
568 
569     set_datetime_bcd(0x02, 0x04, 0x58, 0x02, 0x02, 0x2011);
570 
571     assert_datetime_bcd(0x02, 0x04, 0x58, 0x02, 0x02, 0x2011);
572 
573     /* Since SET flag is still enabled, time does not advance. */
574     clock_step(1000000000LL);
575     assert_datetime_bcd(0x02, 0x04, 0x58, 0x02, 0x02, 0x2011);
576 
577     /* Disable SET flag in Register B */
578     cmos_write(RTC_REG_B, cmos_read(RTC_REG_B) & ~REG_B_SET);
579 
580     assert_datetime_bcd(0x02, 0x04, 0x58, 0x02, 0x02, 0x2011);
581 
582     /* Since SET flag is disabled, the clock now advances.  */
583     clock_step(1000000000LL);
584     assert_datetime_bcd(0x02, 0x04, 0x59, 0x02, 0x02, 0x2011);
585 }
586 
587 static void divider_reset(void)
588 {
589     /* Enable binary-coded decimal (BCD) mode in Register B*/
590     cmos_write(RTC_REG_B, REG_B_24H);
591 
592     /* Enter divider reset */
593     cmos_write(RTC_REG_A, 0x76);
594     set_datetime_bcd(0x02, 0x04, 0x58, 0x02, 0x02, 0x2011);
595 
596     assert_datetime_bcd(0x02, 0x04, 0x58, 0x02, 0x02, 0x2011);
597 
598     /* Since divider reset flag is still enabled, these are equality checks. */
599     clock_step(1000000000LL);
600     assert_datetime_bcd(0x02, 0x04, 0x58, 0x02, 0x02, 0x2011);
601 
602     /* The first update ends 500 ms after divider reset */
603     cmos_write(RTC_REG_A, 0x26);
604     clock_step(500000000LL - UIP_HOLD_LENGTH - 1);
605     g_assert_cmpint(cmos_read(RTC_REG_A) & REG_A_UIP, ==, 0);
606     assert_datetime_bcd(0x02, 0x04, 0x58, 0x02, 0x02, 0x2011);
607 
608     clock_step(1);
609     g_assert_cmpint(cmos_read(RTC_REG_A) & REG_A_UIP, !=, 0);
610     clock_step(UIP_HOLD_LENGTH);
611     g_assert_cmpint(cmos_read(RTC_REG_A) & REG_A_UIP, ==, 0);
612 
613     assert_datetime_bcd(0x02, 0x04, 0x59, 0x02, 0x02, 0x2011);
614 }
615 
616 static void uip_stuck(void)
617 {
618     set_datetime(REG_B_24H, 0x02, 0x04, 0x58, 0x02, 0x02, 0x2011);
619 
620     /* The first update ends 500 ms after divider reset */
621     (void)cmos_read(RTC_REG_C);
622     clock_step(500000000LL);
623     g_assert_cmpint(cmos_read(RTC_REG_A) & REG_A_UIP, ==, 0);
624     assert_datetime_bcd(0x02, 0x04, 0x59, 0x02, 0x02, 0x2011);
625 
626     /* UF is now set.  */
627     cmos_write(RTC_HOURS_ALARM, 0x02);
628     cmos_write(RTC_MINUTES_ALARM, 0xC0);
629     cmos_write(RTC_SECONDS_ALARM, 0xC0);
630 
631     /* Because the alarm will fire soon, reading register A will latch UIP.  */
632     clock_step(1000000000LL - UIP_HOLD_LENGTH / 2);
633     g_assert_cmpint(cmos_read(RTC_REG_A) & REG_A_UIP, !=, 0);
634 
635     /* Move the alarm far away.  This must not cause UIP to remain stuck!  */
636     cmos_write(RTC_HOURS_ALARM, 0x03);
637     clock_step(UIP_HOLD_LENGTH);
638     g_assert_cmpint(cmos_read(RTC_REG_A) & REG_A_UIP, ==, 0);
639 }
640 
641 #define RTC_PERIOD_CODE1    13   /* 8 Hz */
642 #define RTC_PERIOD_CODE2    15   /* 2 Hz */
643 
644 #define RTC_PERIOD_TEST_NR  50
645 
646 static uint64_t wait_periodic_interrupt(uint64_t real_time)
647 {
648     while (!get_irq(RTC_ISA_IRQ)) {
649         real_time = clock_step_next();
650     }
651 
652     g_assert((cmos_read(RTC_REG_C) & REG_C_PF) != 0);
653     return real_time;
654 }
655 
656 static void periodic_timer(void)
657 {
658     int i;
659     uint64_t period_clocks, period_time, start_time, real_time;
660 
661     /* disable all interrupts. */
662     cmos_write(RTC_REG_B, cmos_read(RTC_REG_B) &
663                                    ~(REG_B_PIE | REG_B_AIE | REG_B_UIE));
664     cmos_write(RTC_REG_A, RTC_PERIOD_CODE1);
665     /* enable periodic interrupt after properly configure the period. */
666     cmos_write(RTC_REG_B, cmos_read(RTC_REG_B) | REG_B_PIE);
667 
668     start_time = real_time = clock_step_next();
669 
670     for (i = 0; i < RTC_PERIOD_TEST_NR; i++) {
671         cmos_write(RTC_REG_A, RTC_PERIOD_CODE1);
672         real_time = wait_periodic_interrupt(real_time);
673         cmos_write(RTC_REG_A, RTC_PERIOD_CODE2);
674         real_time = wait_periodic_interrupt(real_time);
675     }
676 
677     period_clocks = periodic_period_to_clock(RTC_PERIOD_CODE1) +
678                        periodic_period_to_clock(RTC_PERIOD_CODE2);
679     period_clocks *= RTC_PERIOD_TEST_NR;
680     period_time = periodic_clock_to_ns(period_clocks);
681 
682     real_time -= start_time;
683     g_assert_cmpint(ABS((int64_t)(real_time - period_time)), <=,
684                     NANOSECONDS_PER_SECOND * 0.5);
685 }
686 
687 int main(int argc, char **argv)
688 {
689     QTestState *s;
690     int ret;
691 
692     g_test_init(&argc, &argv, NULL);
693 
694     s = qtest_start("-rtc clock=vm");
695     qtest_irq_intercept_in(s, "ioapic");
696 
697     qtest_add_func("/rtc/check-time/bcd", bcd_check_time);
698     qtest_add_func("/rtc/check-time/dec", dec_check_time);
699     qtest_add_func("/rtc/alarm/interrupt", alarm_time);
700     qtest_add_func("/rtc/alarm/am-pm", am_pm_alarm);
701     qtest_add_func("/rtc/basic/dec-24h", basic_24h_dec);
702     qtest_add_func("/rtc/basic/bcd-24h", basic_24h_bcd);
703     qtest_add_func("/rtc/basic/dec-12h", basic_12h_dec);
704     qtest_add_func("/rtc/basic/bcd-12h", basic_12h_bcd);
705     qtest_add_func("/rtc/set-year/20xx", set_year_20xx);
706     qtest_add_func("/rtc/set-year/1980", set_year_1980);
707     qtest_add_func("/rtc/update/register_b_set_flag", register_b_set_flag);
708     qtest_add_func("/rtc/update/divider-reset", divider_reset);
709     qtest_add_func("/rtc/update/uip-stuck", uip_stuck);
710     qtest_add_func("/rtc/misc/fuzz-registers", fuzz_registers);
711     qtest_add_func("/rtc/periodic/interrupt", periodic_timer);
712 
713     ret = g_test_run();
714 
715     qtest_quit(s);
716 
717     return ret;
718 }
719