diff options
Diffstat (limited to 'hw/rtc/mc146818rtc.c')
| -rw-r--r-- | hw/rtc/mc146818rtc.c | 79 |
1 files changed, 40 insertions, 39 deletions
diff --git a/hw/rtc/mc146818rtc.c b/hw/rtc/mc146818rtc.c index ee6bf82b40..74ae74bc5c 100644 --- a/hw/rtc/mc146818rtc.c +++ b/hw/rtc/mc146818rtc.c @@ -168,12 +168,13 @@ static uint32_t rtc_periodic_clock_ticks(RTCState *s) * is just due to period adjustment. */ static void -periodic_timer_update(RTCState *s, int64_t current_time, uint32_t old_period) +periodic_timer_update(RTCState *s, int64_t current_time, uint32_t old_period, bool period_change) { uint32_t period; int64_t cur_clock, next_irq_clock, lost_clock = 0; period = rtc_periodic_clock_ticks(s); + s->period = period; if (!period) { s->irq_coalesced = 0; @@ -189,7 +190,7 @@ periodic_timer_update(RTCState *s, int64_t current_time, uint32_t old_period) * if the periodic timer's update is due to period re-configuration, * we should count the clock since last interrupt. */ - if (old_period) { + if (old_period && period_change) { int64_t last_periodic_clock, next_periodic_clock; next_periodic_clock = muldiv64(s->next_periodic_time, @@ -197,42 +198,41 @@ periodic_timer_update(RTCState *s, int64_t current_time, uint32_t old_period) last_periodic_clock = next_periodic_clock - old_period; lost_clock = cur_clock - last_periodic_clock; assert(lost_clock >= 0); + } + /* + * s->irq_coalesced can change for two reasons: + * + * a) if one or more periodic timer interrupts have been lost, + * lost_clock will be more that a period. + * + * b) when the period may be reconfigured, we expect the OS to + * treat delayed tick as the new period. So, when switching + * from a shorter to a longer period, scale down the missing, + * because the OS will treat past delayed ticks as longer + * (leftovers are put back into lost_clock). When switching + * to a shorter period, scale up the missing ticks since the + * OS handler will treat past delayed ticks as shorter. + */ + if (s->lost_tick_policy == LOST_TICK_POLICY_SLEW) { + uint32_t old_irq_coalesced = s->irq_coalesced; + + lost_clock += old_irq_coalesced * old_period; + s->irq_coalesced = lost_clock / s->period; + lost_clock %= s->period; + if (old_irq_coalesced != s->irq_coalesced || + old_period != s->period) { + DPRINTF_C("cmos: coalesced irqs scaled from %d to %d, " + "period scaled from %d to %d\n", old_irq_coalesced, + s->irq_coalesced, old_period, s->period); + rtc_coalesced_timer_update(s); + } + } else { /* - * s->irq_coalesced can change for two reasons: - * - * a) if one or more periodic timer interrupts have been lost, - * lost_clock will be more that a period. - * - * b) when the period may be reconfigured, we expect the OS to - * treat delayed tick as the new period. So, when switching - * from a shorter to a longer period, scale down the missing, - * because the OS will treat past delayed ticks as longer - * (leftovers are put back into lost_clock). When switching - * to a shorter period, scale up the missing ticks since the - * OS handler will treat past delayed ticks as shorter. + * no way to compensate the interrupt if LOST_TICK_POLICY_SLEW + * is not used, we should make the time progress anyway. */ - if (s->lost_tick_policy == LOST_TICK_POLICY_SLEW) { - uint32_t old_irq_coalesced = s->irq_coalesced; - - s->period = period; - lost_clock += old_irq_coalesced * old_period; - s->irq_coalesced = lost_clock / s->period; - lost_clock %= s->period; - if (old_irq_coalesced != s->irq_coalesced || - old_period != s->period) { - DPRINTF_C("cmos: coalesced irqs scaled from %d to %d, " - "period scaled from %d to %d\n", old_irq_coalesced, - s->irq_coalesced, old_period, s->period); - rtc_coalesced_timer_update(s); - } - } else { - /* - * no way to compensate the interrupt if LOST_TICK_POLICY_SLEW - * is not used, we should make the time progress anyway. - */ - lost_clock = MIN(lost_clock, period); - } + lost_clock = MIN(lost_clock, period); } assert(lost_clock >= 0 && lost_clock <= period); @@ -246,7 +246,7 @@ static void rtc_periodic_timer(void *opaque) { RTCState *s = opaque; - periodic_timer_update(s, s->next_periodic_time, 0); + periodic_timer_update(s, s->next_periodic_time, s->period, false); s->cmos_data[RTC_REG_C] |= REG_C_PF; if (s->cmos_data[RTC_REG_B] & REG_B_PIE) { s->cmos_data[RTC_REG_C] |= REG_C_IRQF; @@ -512,7 +512,7 @@ static void cmos_ioport_write(void *opaque, hwaddr addr, if (update_periodic_timer) { periodic_timer_update(s, qemu_clock_get_ns(rtc_clock), - old_period); + old_period, true); } check_update_timer(s); @@ -551,7 +551,7 @@ static void cmos_ioport_write(void *opaque, hwaddr addr, if (update_periodic_timer) { periodic_timer_update(s, qemu_clock_get_ns(rtc_clock), - old_period); + old_period, true); } check_update_timer(s); @@ -795,6 +795,7 @@ static int rtc_post_load(void *opaque, int version_id) s->offset = 0; check_update_timer(s); } + s->period = rtc_periodic_clock_ticks(s); /* The periodic timer is deterministic in record/replay mode, * so there is no need to update it after loading the vmstate. @@ -804,7 +805,7 @@ static int rtc_post_load(void *opaque, int version_id) uint64_t now = qemu_clock_get_ns(rtc_clock); if (now < s->next_periodic_time || now > (s->next_periodic_time + get_max_clock_jump())) { - periodic_timer_update(s, qemu_clock_get_ns(rtc_clock), 0); + periodic_timer_update(s, qemu_clock_get_ns(rtc_clock), s->period, false); } } |