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qemu-e2k/hw/mc146818rtc.c
aliguori 73822ec806 Add -rtc-td-hack option to fix time drift with RTC on Windows (Gleb Natapov) 
After my last patch to fix interrupt coalescing was rejected
on the basis that it is too intrusive we decided to make the
fix much more localized and only fix the problem for RTC time
source. Unfortunately it is impossible to fix the problem entirely
inside RTC code like Andrzej proposed since Windows reads RTC
register C more then once on each time interrupt so it is impossible
to count reliably how many interrupt windows actually handled.
Proposed solution is localized to I386 target and is disabled by
default. To enable it "-rtc-td-hack" flag should be used.

Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>



git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@6320 c046a42c-6fe2-441c-8c8c-71466251a162
2009-01-15 20:11:34 +00:00

671 lines
19 KiB
C
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/*
* QEMU MC146818 RTC emulation
*
* Copyright (c) 2003-2004 Fabrice Bellard
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include "hw.h"
#include "qemu-timer.h"
#include "sysemu.h"
#include "pc.h"
#include "isa.h"
#include "hpet_emul.h"
//#define DEBUG_CMOS
#define RTC_SECONDS 0
#define RTC_SECONDS_ALARM 1
#define RTC_MINUTES 2
#define RTC_MINUTES_ALARM 3
#define RTC_HOURS 4
#define RTC_HOURS_ALARM 5
#define RTC_ALARM_DONT_CARE 0xC0
#define RTC_DAY_OF_WEEK 6
#define RTC_DAY_OF_MONTH 7
#define RTC_MONTH 8
#define RTC_YEAR 9
#define RTC_REG_A 10
#define RTC_REG_B 11
#define RTC_REG_C 12
#define RTC_REG_D 13
#define REG_A_UIP 0x80
#define REG_B_SET 0x80
#define REG_B_PIE 0x40
#define REG_B_AIE 0x20
#define REG_B_UIE 0x10
#define REG_B_DM 0x04
struct RTCState {
uint8_t cmos_data[128];
uint8_t cmos_index;
struct tm current_tm;
qemu_irq irq;
int it_shift;
/* periodic timer */
QEMUTimer *periodic_timer;
int64_t next_periodic_time;
/* second update */
int64_t next_second_time;
#ifdef TARGET_I386
uint32_t irq_coalesced;
uint32_t period;
#endif
QEMUTimer *second_timer;
QEMUTimer *second_timer2;
};
static void rtc_irq_raise(qemu_irq irq) {
/* When HPET is operating in legacy mode, RTC interrupts are disabled
* We block qemu_irq_raise, but not qemu_irq_lower, in case legacy
* mode is established while interrupt is raised. We want it to
* be lowered in any case
*/
#if defined TARGET_I386 || defined TARGET_X86_64
if (!hpet_in_legacy_mode())
#endif
qemu_irq_raise(irq);
}
static void rtc_set_time(RTCState *s);
static void rtc_copy_date(RTCState *s);
static void rtc_timer_update(RTCState *s, int64_t current_time)
{
int period_code, period;
int64_t cur_clock, next_irq_clock;
period_code = s->cmos_data[RTC_REG_A] & 0x0f;
#if defined TARGET_I386 || defined TARGET_X86_64
/* disable periodic timer if hpet is in legacy mode, since interrupts are
* disabled anyway.
*/
if (period_code != 0 && (s->cmos_data[RTC_REG_B] & REG_B_PIE) && !hpet_in_legacy_mode()) {
#else
if (period_code != 0 && (s->cmos_data[RTC_REG_B] & REG_B_PIE)) {
#endif
if (period_code <= 2)
period_code += 7;
/* period in 32 Khz cycles */
period = 1 << (period_code - 1);
#ifdef TARGET_I386
if(period != s->period)
s->irq_coalesced = (s->irq_coalesced * s->period) / period;
s->period = period;
#endif
/* compute 32 khz clock */
cur_clock = muldiv64(current_time, 32768, ticks_per_sec);
next_irq_clock = (cur_clock & ~(period - 1)) + period;
s->next_periodic_time = muldiv64(next_irq_clock, ticks_per_sec, 32768) + 1;
qemu_mod_timer(s->periodic_timer, s->next_periodic_time);
} else {
#ifdef TARGET_I386
s->irq_coalesced = 0;
#endif
qemu_del_timer(s->periodic_timer);
}
}
static void rtc_periodic_timer(void *opaque)
{
RTCState *s = opaque;
rtc_timer_update(s, s->next_periodic_time);
#ifdef TARGET_I386
if ((s->cmos_data[RTC_REG_C] & 0xc0) && rtc_td_hack) {
s->irq_coalesced++;
return;
}
#endif
s->cmos_data[RTC_REG_C] |= 0xc0;
rtc_irq_raise(s->irq);
}
static void cmos_ioport_write(void *opaque, uint32_t addr, uint32_t data)
{
RTCState *s = opaque;
if ((addr & 1) == 0) {
s->cmos_index = data & 0x7f;
} else {
#ifdef DEBUG_CMOS
printf("cmos: write index=0x%02x val=0x%02x\n",
s->cmos_index, data);
#endif
switch(s->cmos_index) {
case RTC_SECONDS_ALARM:
case RTC_MINUTES_ALARM:
case RTC_HOURS_ALARM:
/* XXX: not supported */
s->cmos_data[s->cmos_index] = data;
break;
case RTC_SECONDS:
case RTC_MINUTES:
case RTC_HOURS:
case RTC_DAY_OF_WEEK:
case RTC_DAY_OF_MONTH:
case RTC_MONTH:
case RTC_YEAR:
s->cmos_data[s->cmos_index] = data;
/* if in set mode, do not update the time */
if (!(s->cmos_data[RTC_REG_B] & REG_B_SET)) {
rtc_set_time(s);
}
break;
case RTC_REG_A:
/* UIP bit is read only */
s->cmos_data[RTC_REG_A] = (data & ~REG_A_UIP) |
(s->cmos_data[RTC_REG_A] & REG_A_UIP);
rtc_timer_update(s, qemu_get_clock(vm_clock));
break;
case RTC_REG_B:
if (data & REG_B_SET) {
/* set mode: reset UIP mode */
s->cmos_data[RTC_REG_A] &= ~REG_A_UIP;
data &= ~REG_B_UIE;
} else {
/* if disabling set mode, update the time */
if (s->cmos_data[RTC_REG_B] & REG_B_SET) {
rtc_set_time(s);
}
}
s->cmos_data[RTC_REG_B] = data;
rtc_timer_update(s, qemu_get_clock(vm_clock));
break;
case RTC_REG_C:
case RTC_REG_D:
/* cannot write to them */
break;
default:
s->cmos_data[s->cmos_index] = data;
break;
}
}
}
static inline int to_bcd(RTCState *s, int a)
{
if (s->cmos_data[RTC_REG_B] & REG_B_DM) {
return a;
} else {
return ((a / 10) << 4) | (a % 10);
}
}
static inline int from_bcd(RTCState *s, int a)
{
if (s->cmos_data[RTC_REG_B] & REG_B_DM) {
return a;
} else {
return ((a >> 4) * 10) + (a & 0x0f);
}
}
static void rtc_set_time(RTCState *s)
{
struct tm *tm = &s->current_tm;
tm->tm_sec = from_bcd(s, s->cmos_data[RTC_SECONDS]);
tm->tm_min = from_bcd(s, s->cmos_data[RTC_MINUTES]);
tm->tm_hour = from_bcd(s, s->cmos_data[RTC_HOURS] & 0x7f);
if (!(s->cmos_data[RTC_REG_B] & 0x02) &&
(s->cmos_data[RTC_HOURS] & 0x80)) {
tm->tm_hour += 12;
}
tm->tm_wday = from_bcd(s, s->cmos_data[RTC_DAY_OF_WEEK]) - 1;
tm->tm_mday = from_bcd(s, s->cmos_data[RTC_DAY_OF_MONTH]);
tm->tm_mon = from_bcd(s, s->cmos_data[RTC_MONTH]) - 1;
tm->tm_year = from_bcd(s, s->cmos_data[RTC_YEAR]) + 100;
}
static void rtc_copy_date(RTCState *s)
{
const struct tm *tm = &s->current_tm;
s->cmos_data[RTC_SECONDS] = to_bcd(s, tm->tm_sec);
s->cmos_data[RTC_MINUTES] = to_bcd(s, tm->tm_min);
if (s->cmos_data[RTC_REG_B] & 0x02) {
/* 24 hour format */
s->cmos_data[RTC_HOURS] = to_bcd(s, tm->tm_hour);
} else {
/* 12 hour format */
s->cmos_data[RTC_HOURS] = to_bcd(s, tm->tm_hour % 12);
if (tm->tm_hour >= 12)
s->cmos_data[RTC_HOURS] |= 0x80;
}
s->cmos_data[RTC_DAY_OF_WEEK] = to_bcd(s, tm->tm_wday + 1);
s->cmos_data[RTC_DAY_OF_MONTH] = to_bcd(s, tm->tm_mday);
s->cmos_data[RTC_MONTH] = to_bcd(s, tm->tm_mon + 1);
s->cmos_data[RTC_YEAR] = to_bcd(s, tm->tm_year % 100);
}
/* month is between 0 and 11. */
static int get_days_in_month(int month, int year)
{
static const int days_tab[12] = {
31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
};
int d;
if ((unsigned )month >= 12)
return 31;
d = days_tab[month];
if (month == 1) {
if ((year % 4) == 0 && ((year % 100) != 0 || (year % 400) == 0))
d++;
}
return d;
}
/* update 'tm' to the next second */
static void rtc_next_second(struct tm *tm)
{
int days_in_month;
tm->tm_sec++;
if ((unsigned)tm->tm_sec >= 60) {
tm->tm_sec = 0;
tm->tm_min++;
if ((unsigned)tm->tm_min >= 60) {
tm->tm_min = 0;
tm->tm_hour++;
if ((unsigned)tm->tm_hour >= 24) {
tm->tm_hour = 0;
/* next day */
tm->tm_wday++;
if ((unsigned)tm->tm_wday >= 7)
tm->tm_wday = 0;
days_in_month = get_days_in_month(tm->tm_mon,
tm->tm_year + 1900);
tm->tm_mday++;
if (tm->tm_mday < 1) {
tm->tm_mday = 1;
} else if (tm->tm_mday > days_in_month) {
tm->tm_mday = 1;
tm->tm_mon++;
if (tm->tm_mon >= 12) {
tm->tm_mon = 0;
tm->tm_year++;
}
}
}
}
}
}
static void rtc_update_second(void *opaque)
{
RTCState *s = opaque;
int64_t delay;
/* if the oscillator is not in normal operation, we do not update */
if ((s->cmos_data[RTC_REG_A] & 0x70) != 0x20) {
s->next_second_time += ticks_per_sec;
qemu_mod_timer(s->second_timer, s->next_second_time);
} else {
rtc_next_second(&s->current_tm);
if (!(s->cmos_data[RTC_REG_B] & REG_B_SET)) {
/* update in progress bit */
s->cmos_data[RTC_REG_A] |= REG_A_UIP;
}
/* should be 244 us = 8 / 32768 seconds, but currently the
timers do not have the necessary resolution. */
delay = (ticks_per_sec * 1) / 100;
if (delay < 1)
delay = 1;
qemu_mod_timer(s->second_timer2,
s->next_second_time + delay);
}
}
static void rtc_update_second2(void *opaque)
{
RTCState *s = opaque;
if (!(s->cmos_data[RTC_REG_B] & REG_B_SET)) {
rtc_copy_date(s);
}
/* check alarm */
if (s->cmos_data[RTC_REG_B] & REG_B_AIE) {
if (((s->cmos_data[RTC_SECONDS_ALARM] & 0xc0) == 0xc0 ||
s->cmos_data[RTC_SECONDS_ALARM] == s->current_tm.tm_sec) &&
((s->cmos_data[RTC_MINUTES_ALARM] & 0xc0) == 0xc0 ||
s->cmos_data[RTC_MINUTES_ALARM] == s->current_tm.tm_mon) &&
((s->cmos_data[RTC_HOURS_ALARM] & 0xc0) == 0xc0 ||
s->cmos_data[RTC_HOURS_ALARM] == s->current_tm.tm_hour)) {
s->cmos_data[RTC_REG_C] |= 0xa0;
rtc_irq_raise(s->irq);
}
}
/* update ended interrupt */
if (s->cmos_data[RTC_REG_B] & REG_B_UIE) {
s->cmos_data[RTC_REG_C] |= 0x90;
rtc_irq_raise(s->irq);
}
/* clear update in progress bit */
s->cmos_data[RTC_REG_A] &= ~REG_A_UIP;
s->next_second_time += ticks_per_sec;
qemu_mod_timer(s->second_timer, s->next_second_time);
}
static uint32_t cmos_ioport_read(void *opaque, uint32_t addr)
{
RTCState *s = opaque;
int ret;
if ((addr & 1) == 0) {
return 0xff;
} else {
switch(s->cmos_index) {
case RTC_SECONDS:
case RTC_MINUTES:
case RTC_HOURS:
case RTC_DAY_OF_WEEK:
case RTC_DAY_OF_MONTH:
case RTC_MONTH:
case RTC_YEAR:
ret = s->cmos_data[s->cmos_index];
break;
case RTC_REG_A:
ret = s->cmos_data[s->cmos_index];
break;
case RTC_REG_C:
ret = s->cmos_data[s->cmos_index];
qemu_irq_lower(s->irq);
#ifdef TARGET_I386
if(s->irq_coalesced) {
apic_reset_irq_delivered();
qemu_irq_raise(s->irq);
if (apic_get_irq_delivered())
s->irq_coalesced--;
break;
}
#endif
s->cmos_data[RTC_REG_C] = 0x00;
break;
default:
ret = s->cmos_data[s->cmos_index];
break;
}
#ifdef DEBUG_CMOS
printf("cmos: read index=0x%02x val=0x%02x\n",
s->cmos_index, ret);
#endif
return ret;
}
}
void rtc_set_memory(RTCState *s, int addr, int val)
{
if (addr >= 0 && addr <= 127)
s->cmos_data[addr] = val;
}
void rtc_set_date(RTCState *s, const struct tm *tm)
{
s->current_tm = *tm;
rtc_copy_date(s);
}
/* PC cmos mappings */
#define REG_IBM_CENTURY_BYTE 0x32
#define REG_IBM_PS2_CENTURY_BYTE 0x37
static void rtc_set_date_from_host(RTCState *s)
{
struct tm tm;
int val;
/* set the CMOS date */
qemu_get_timedate(&tm, 0);
rtc_set_date(s, &tm);
val = to_bcd(s, (tm.tm_year / 100) + 19);
rtc_set_memory(s, REG_IBM_CENTURY_BYTE, val);
rtc_set_memory(s, REG_IBM_PS2_CENTURY_BYTE, val);
}
static void rtc_save(QEMUFile *f, void *opaque)
{
RTCState *s = opaque;
qemu_put_buffer(f, s->cmos_data, 128);
qemu_put_8s(f, &s->cmos_index);
qemu_put_be32(f, s->current_tm.tm_sec);
qemu_put_be32(f, s->current_tm.tm_min);
qemu_put_be32(f, s->current_tm.tm_hour);
qemu_put_be32(f, s->current_tm.tm_wday);
qemu_put_be32(f, s->current_tm.tm_mday);
qemu_put_be32(f, s->current_tm.tm_mon);
qemu_put_be32(f, s->current_tm.tm_year);
qemu_put_timer(f, s->periodic_timer);
qemu_put_be64(f, s->next_periodic_time);
qemu_put_be64(f, s->next_second_time);
qemu_put_timer(f, s->second_timer);
qemu_put_timer(f, s->second_timer2);
}
static int rtc_load(QEMUFile *f, void *opaque, int version_id)
{
RTCState *s = opaque;
if (version_id != 1)
return -EINVAL;
qemu_get_buffer(f, s->cmos_data, 128);
qemu_get_8s(f, &s->cmos_index);
s->current_tm.tm_sec=qemu_get_be32(f);
s->current_tm.tm_min=qemu_get_be32(f);
s->current_tm.tm_hour=qemu_get_be32(f);
s->current_tm.tm_wday=qemu_get_be32(f);
s->current_tm.tm_mday=qemu_get_be32(f);
s->current_tm.tm_mon=qemu_get_be32(f);
s->current_tm.tm_year=qemu_get_be32(f);
qemu_get_timer(f, s->periodic_timer);
s->next_periodic_time=qemu_get_be64(f);
s->next_second_time=qemu_get_be64(f);
qemu_get_timer(f, s->second_timer);
qemu_get_timer(f, s->second_timer2);
return 0;
}
#ifdef TARGET_I386
static void rtc_save_td(QEMUFile *f, void *opaque)
{
RTCState *s = opaque;
qemu_put_be32(f, s->irq_coalesced);
qemu_put_be32(f, s->period);
}
static int rtc_load_td(QEMUFile *f, void *opaque, int version_id)
{
RTCState *s = opaque;
if (version_id != 1)
return -EINVAL;
s->irq_coalesced = qemu_get_be32(f);
s->period = qemu_get_be32(f);
return 0;
}
#endif
RTCState *rtc_init(int base, qemu_irq irq)
{
RTCState *s;
s = qemu_mallocz(sizeof(RTCState));
if (!s)
return NULL;
s->irq = irq;
s->cmos_data[RTC_REG_A] = 0x26;
s->cmos_data[RTC_REG_B] = 0x02;
s->cmos_data[RTC_REG_C] = 0x00;
s->cmos_data[RTC_REG_D] = 0x80;
rtc_set_date_from_host(s);
s->periodic_timer = qemu_new_timer(vm_clock,
rtc_periodic_timer, s);
s->second_timer = qemu_new_timer(vm_clock,
rtc_update_second, s);
s->second_timer2 = qemu_new_timer(vm_clock,
rtc_update_second2, s);
s->next_second_time = qemu_get_clock(vm_clock) + (ticks_per_sec * 99) / 100;
qemu_mod_timer(s->second_timer2, s->next_second_time);
register_ioport_write(base, 2, 1, cmos_ioport_write, s);
register_ioport_read(base, 2, 1, cmos_ioport_read, s);
register_savevm("mc146818rtc", base, 1, rtc_save, rtc_load, s);
#ifdef TARGET_I386
if (rtc_td_hack)
register_savevm("mc146818rtc-td", base, 1, rtc_save_td, rtc_load_td, s);
#endif
return s;
}
/* Memory mapped interface */
static uint32_t cmos_mm_readb (void *opaque, target_phys_addr_t addr)
{
RTCState *s = opaque;
return cmos_ioport_read(s, addr >> s->it_shift) & 0xFF;
}
static void cmos_mm_writeb (void *opaque,
target_phys_addr_t addr, uint32_t value)
{
RTCState *s = opaque;
cmos_ioport_write(s, addr >> s->it_shift, value & 0xFF);
}
static uint32_t cmos_mm_readw (void *opaque, target_phys_addr_t addr)
{
RTCState *s = opaque;
uint32_t val;
val = cmos_ioport_read(s, addr >> s->it_shift) & 0xFFFF;
#ifdef TARGET_WORDS_BIGENDIAN
val = bswap16(val);
#endif
return val;
}
static void cmos_mm_writew (void *opaque,
target_phys_addr_t addr, uint32_t value)
{
RTCState *s = opaque;
#ifdef TARGET_WORDS_BIGENDIAN
value = bswap16(value);
#endif
cmos_ioport_write(s, addr >> s->it_shift, value & 0xFFFF);
}
static uint32_t cmos_mm_readl (void *opaque, target_phys_addr_t addr)
{
RTCState *s = opaque;
uint32_t val;
val = cmos_ioport_read(s, addr >> s->it_shift);
#ifdef TARGET_WORDS_BIGENDIAN
val = bswap32(val);
#endif
return val;
}
static void cmos_mm_writel (void *opaque,
target_phys_addr_t addr, uint32_t value)
{
RTCState *s = opaque;
#ifdef TARGET_WORDS_BIGENDIAN
value = bswap32(value);
#endif
cmos_ioport_write(s, addr >> s->it_shift, value);
}
static CPUReadMemoryFunc *rtc_mm_read[] = {
&cmos_mm_readb,
&cmos_mm_readw,
&cmos_mm_readl,
};
static CPUWriteMemoryFunc *rtc_mm_write[] = {
&cmos_mm_writeb,
&cmos_mm_writew,
&cmos_mm_writel,
};
RTCState *rtc_mm_init(target_phys_addr_t base, int it_shift, qemu_irq irq)
{
RTCState *s;
int io_memory;
s = qemu_mallocz(sizeof(RTCState));
if (!s)
return NULL;
s->irq = irq;
s->cmos_data[RTC_REG_A] = 0x26;
s->cmos_data[RTC_REG_B] = 0x02;
s->cmos_data[RTC_REG_C] = 0x00;
s->cmos_data[RTC_REG_D] = 0x80;
rtc_set_date_from_host(s);
s->periodic_timer = qemu_new_timer(vm_clock,
rtc_periodic_timer, s);
s->second_timer = qemu_new_timer(vm_clock,
rtc_update_second, s);
s->second_timer2 = qemu_new_timer(vm_clock,
rtc_update_second2, s);
s->next_second_time = qemu_get_clock(vm_clock) + (ticks_per_sec * 99) / 100;
qemu_mod_timer(s->second_timer2, s->next_second_time);
io_memory = cpu_register_io_memory(0, rtc_mm_read, rtc_mm_write, s);
cpu_register_physical_memory(base, 2 << it_shift, io_memory);
register_savevm("mc146818rtc", base, 1, rtc_save, rtc_load, s);
#ifdef TARGET_I386
if (rtc_td_hack)
register_savevm("mc146818rtc-td", base, 1, rtc_save_td, rtc_load_td, s);
#endif
return s;
}
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