diff options
| -rw-r--r-- | hw/mc146818rtc.c | 117 |
1 files changed, 103 insertions, 14 deletions
diff --git a/hw/mc146818rtc.c b/hw/mc146818rtc.c index cb65c4f..9d530a8 100644 --- a/hw/mc146818rtc.c +++ b/hw/mc146818rtc.c @@ -46,6 +46,11 @@ #endif #define NSEC_PER_SEC 1000000000LL +#define SEC_PER_MIN 60 +#define MIN_PER_HOUR 60 +#define SEC_PER_HOUR 3600 +#define HOUR_PER_DAY 24 +#define SEC_PER_DAY 86400 #define RTC_REINJECT_ON_ACK_COUNT 20 #define RTC_CLOCK_RATE 32768 @@ -69,6 +74,7 @@ typedef struct RTCState { int64_t next_periodic_time; /* update-ended timer */ QEMUTimer *update_timer; + uint64_t next_alarm_time; uint16_t irq_reinject_on_ack_count; uint32_t irq_coalesced; uint32_t period; @@ -82,6 +88,7 @@ static void rtc_set_time(RTCState *s); static void rtc_update_time(RTCState *s); static void rtc_set_cmos(RTCState *s); static inline int rtc_from_bcd(RTCState *s, int a); +static uint64_t get_next_alarm(RTCState *s); static inline bool rtc_running(RTCState *s) { @@ -204,6 +211,7 @@ static void check_update_timer(RTCState *s) { uint64_t next_update_time; uint64_t guest_nsec; + int next_alarm_sec; /* From the data sheet: "Holding the dividers in reset prevents * interrupts from operating, while setting the SET bit allows" @@ -226,9 +234,21 @@ static void check_update_timer(RTCState *s) } guest_nsec = get_guest_rtc_ns(s) % NSEC_PER_SEC; - /* reprogram to next second */ + /* if UF is clear, reprogram to next second */ next_update_time = qemu_get_clock_ns(rtc_clock) + NSEC_PER_SEC - guest_nsec; + + /* Compute time of next alarm. One second is already accounted + * for in next_update_time. + */ + next_alarm_sec = get_next_alarm(s); + s->next_alarm_time = next_update_time + (next_alarm_sec - 1) * NSEC_PER_SEC; + + if (s->cmos_data[RTC_REG_C] & REG_C_UF) { + /* UF is set, but AF is clear. Program the timer to target + * the alarm time. */ + next_update_time = s->next_alarm_time; + } if (next_update_time != qemu_timer_expire_time_ns(s->update_timer)) { qemu_mod_timer(s->update_timer, next_update_time); } @@ -245,31 +265,95 @@ static inline uint8_t convert_hour(RTCState *s, uint8_t hour) return hour; } -static uint32_t check_alarm(RTCState *s) +static uint64_t get_next_alarm(RTCState *s) { - uint8_t alarm_hour, alarm_min, alarm_sec; - uint8_t cur_hour, cur_min, cur_sec; + int32_t alarm_sec, alarm_min, alarm_hour, cur_hour, cur_min, cur_sec; + int32_t hour, min, sec; + + rtc_update_time(s); alarm_sec = rtc_from_bcd(s, s->cmos_data[RTC_SECONDS_ALARM]); alarm_min = rtc_from_bcd(s, s->cmos_data[RTC_MINUTES_ALARM]); alarm_hour = rtc_from_bcd(s, s->cmos_data[RTC_HOURS_ALARM]); - alarm_hour = convert_hour(s, alarm_hour); + alarm_hour = alarm_hour == -1 ? -1 : convert_hour(s, alarm_hour); cur_sec = rtc_from_bcd(s, s->cmos_data[RTC_SECONDS]); cur_min = rtc_from_bcd(s, s->cmos_data[RTC_MINUTES]); cur_hour = rtc_from_bcd(s, s->cmos_data[RTC_HOURS]); cur_hour = convert_hour(s, cur_hour); - if (((s->cmos_data[RTC_SECONDS_ALARM] & 0xc0) == 0xc0 - || alarm_sec == cur_sec) && - ((s->cmos_data[RTC_MINUTES_ALARM] & 0xc0) == 0xc0 - || alarm_min == cur_min) && - ((s->cmos_data[RTC_HOURS_ALARM] & 0xc0) == 0xc0 - || alarm_hour == cur_hour)) { - return 1; + if (alarm_hour == -1) { + alarm_hour = cur_hour; + if (alarm_min == -1) { + alarm_min = cur_min; + if (alarm_sec == -1) { + alarm_sec = cur_sec + 1; + } else if (cur_sec > alarm_sec) { + alarm_min++; + } + } else if (cur_min == alarm_min) { + if (alarm_sec == -1) { + alarm_sec = cur_sec + 1; + } else { + if (cur_sec > alarm_sec) { + alarm_hour++; + } + } + if (alarm_sec == SEC_PER_MIN) { + /* wrap to next hour, minutes is not in don't care mode */ + alarm_sec = 0; + alarm_hour++; + } + } else if (cur_min > alarm_min) { + alarm_hour++; + } + } else if (cur_hour == alarm_hour) { + if (alarm_min == -1) { + alarm_min = cur_min; + if (alarm_sec == -1) { + alarm_sec = cur_sec + 1; + } else if (cur_sec > alarm_sec) { + alarm_min++; + } + + if (alarm_sec == SEC_PER_MIN) { + alarm_sec = 0; + alarm_min++; + } + /* wrap to next day, hour is not in don't care mode */ + alarm_min %= MIN_PER_HOUR; + } else if (cur_min == alarm_min) { + if (alarm_sec == -1) { + alarm_sec = cur_sec + 1; + } + /* wrap to next day, hours+minutes not in don't care mode */ + alarm_sec %= SEC_PER_MIN; + } } - return 0; + /* values that are still don't care fire at the next min/sec */ + if (alarm_min == -1) { + alarm_min = 0; + } + if (alarm_sec == -1) { + alarm_sec = 0; + } + + /* keep values in range */ + if (alarm_sec == SEC_PER_MIN) { + alarm_sec = 0; + alarm_min++; + } + if (alarm_min == MIN_PER_HOUR) { + alarm_min = 0; + alarm_hour++; + } + alarm_hour %= HOUR_PER_DAY; + + hour = alarm_hour - cur_hour; + min = hour * MIN_PER_HOUR + alarm_min - cur_min; + sec = min * SEC_PER_MIN + alarm_sec - cur_sec; + return sec <= 0 ? sec + SEC_PER_DAY : sec; } static void rtc_update_timer(void *opaque) @@ -284,12 +368,13 @@ static void rtc_update_timer(void *opaque) rtc_update_time(s); s->cmos_data[RTC_REG_A] &= ~REG_A_UIP; - if (check_alarm(s)) { + if (qemu_get_clock_ns(rtc_clock) >= s->next_alarm_time) { irqs |= REG_C_AF; if (s->cmos_data[RTC_REG_B] & REG_B_AIE) { qemu_system_wakeup_request(QEMU_WAKEUP_REASON_RTC); } } + new_irqs = irqs & ~s->cmos_data[RTC_REG_C]; s->cmos_data[RTC_REG_C] |= irqs; if ((new_irqs & s->cmos_data[RTC_REG_B]) != 0) { @@ -407,6 +492,9 @@ static inline int rtc_to_bcd(RTCState *s, int a) static inline int rtc_from_bcd(RTCState *s, int a) { + if ((a & 0xc0) == 0xc0) { + return -1; + } if (s->cmos_data[RTC_REG_B] & REG_B_DM) { return a; } else { @@ -642,6 +730,7 @@ static const VMStateDescription vmstate_rtc = { VMSTATE_UINT64_V(last_update, RTCState, 3), VMSTATE_INT64_V(offset, RTCState, 3), VMSTATE_TIMER_V(update_timer, RTCState, 3), + VMSTATE_UINT64_V(next_alarm_time, RTCState, 3), VMSTATE_END_OF_LIST() } }; |