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xemu/hw/mc146818rtc.c
Aurelien Jarno 51e08f3e4b mc146818rtc: update registers after a format change 
For some unknown reason, the MIPS kernel briefly changes the RTC to
binary mode during boot, switch back to BCD mode and read the time. As
the registers are updated only every second, they may still be in the
old format when they are read.

This patch forces a register update immediately after a format change
(BCD/binary or 12/24H). This avoid long fsck during boot due to time
wrap.

Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
2011-01-29 15:19:22 +01:00

658 lines
20 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 "apic.h"
#include "isa.h"
#include "mc146818rtc.h"
//#define DEBUG_CMOS
//#define DEBUG_COALESCED
#ifdef DEBUG_CMOS
# define CMOS_DPRINTF(format, ...) printf(format, ## __VA_ARGS__)
#else
# define CMOS_DPRINTF(format, ...) do { } while (0)
#endif
#ifdef DEBUG_COALESCED
# define DPRINTF_C(format, ...) printf(format, ## __VA_ARGS__)
#else
# define DPRINTF_C(format, ...) do { } while (0)
#endif
#define RTC_REINJECT_ON_ACK_COUNT 20
#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_SQWE 0x08
#define REG_B_DM 0x04
#define REG_B_24H 0x02
#define REG_C_UF 0x10
#define REG_C_IRQF 0x80
#define REG_C_PF 0x40
#define REG_C_AF 0x20
typedef struct RTCState {
ISADevice dev;
uint8_t cmos_data[128];
uint8_t cmos_index;
struct tm current_tm;
int32_t base_year;
qemu_irq irq;
qemu_irq sqw_irq;
int it_shift;
/* periodic timer */
QEMUTimer *periodic_timer;
int64_t next_periodic_time;
/* second update */
int64_t next_second_time;
uint16_t irq_reinject_on_ack_count;
uint32_t irq_coalesced;
uint32_t period;
QEMUTimer *coalesced_timer;
QEMUTimer *second_timer;
QEMUTimer *second_timer2;
} RTCState;
static void rtc_set_time(RTCState *s);
static void rtc_copy_date(RTCState *s);
#ifdef TARGET_I386
static void rtc_coalesced_timer_update(RTCState *s)
{
if (s->irq_coalesced == 0) {
qemu_del_timer(s->coalesced_timer);
} else {
/* divide each RTC interval to 2 - 8 smaller intervals */
int c = MIN(s->irq_coalesced, 7) + 1;
int64_t next_clock = qemu_get_clock(rtc_clock) +
muldiv64(s->period / c, get_ticks_per_sec(), 32768);
qemu_mod_timer(s->coalesced_timer, next_clock);
}
}
static void rtc_coalesced_timer(void *opaque)
{
RTCState *s = opaque;
if (s->irq_coalesced != 0) {
apic_reset_irq_delivered();
s->cmos_data[RTC_REG_C] |= 0xc0;
DPRINTF_C("cmos: injecting from timer\n");
qemu_irq_raise(s->irq);
if (apic_get_irq_delivered()) {
s->irq_coalesced--;
DPRINTF_C("cmos: coalesced irqs decreased to %d\n",
s->irq_coalesced);
}
}
rtc_coalesced_timer_update(s);
}
#endif
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 (period_code != 0
&& ((s->cmos_data[RTC_REG_B] & REG_B_PIE)
|| ((s->cmos_data[RTC_REG_B] & REG_B_SQWE) && s->sqw_irq))) {
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;
DPRINTF_C("cmos: coalesced irqs scaled to %d\n", s->irq_coalesced);
}
s->period = period;
#endif
/* compute 32 khz clock */
cur_clock = muldiv64(current_time, 32768, get_ticks_per_sec());
next_irq_clock = (cur_clock & ~(period - 1)) + period;
s->next_periodic_time =
muldiv64(next_irq_clock, get_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);
if (s->cmos_data[RTC_REG_B] & REG_B_PIE) {
s->cmos_data[RTC_REG_C] |= 0xc0;
#ifdef TARGET_I386
if(rtc_td_hack) {
if (s->irq_reinject_on_ack_count >= RTC_REINJECT_ON_ACK_COUNT)
s->irq_reinject_on_ack_count = 0;
apic_reset_irq_delivered();
qemu_irq_raise(s->irq);
if (!apic_get_irq_delivered()) {
s->irq_coalesced++;
rtc_coalesced_timer_update(s);
DPRINTF_C("cmos: coalesced irqs increased to %d\n",
s->irq_coalesced);
}
} else
#endif
qemu_irq_raise(s->irq);
}
if (s->cmos_data[RTC_REG_B] & REG_B_SQWE) {
/* Not square wave at all but we don't want 2048Hz interrupts!
Must be seen as a pulse. */
qemu_irq_raise(s->sqw_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 {
CMOS_DPRINTF("cmos: write index=0x%02x val=0x%02x\n",
s->cmos_index, data);
switch(s->cmos_index) {
case RTC_SECONDS_ALARM:
case RTC_MINUTES_ALARM:
case RTC_HOURS_ALARM:
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(rtc_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);
}
}
if (((s->cmos_data[RTC_REG_B] ^ data) & (REG_B_DM | REG_B_24H)) &&
!(data & REG_B_SET)) {
/* If the time format has changed and not in set mode,
update the registers immediately. */
s->cmos_data[RTC_REG_B] = data;
rtc_copy_date(s);
} else {
s->cmos_data[RTC_REG_B] = data;
}
rtc_timer_update(s, qemu_get_clock(rtc_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 rtc_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 rtc_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 = rtc_from_bcd(s, s->cmos_data[RTC_SECONDS]);
tm->tm_min = rtc_from_bcd(s, s->cmos_data[RTC_MINUTES]);
tm->tm_hour = rtc_from_bcd(s, s->cmos_data[RTC_HOURS] & 0x7f);
if (!(s->cmos_data[RTC_REG_B] & REG_B_24H) &&
(s->cmos_data[RTC_HOURS] & 0x80)) {
tm->tm_hour += 12;
}
tm->tm_wday = rtc_from_bcd(s, s->cmos_data[RTC_DAY_OF_WEEK]) - 1;
tm->tm_mday = rtc_from_bcd(s, s->cmos_data[RTC_DAY_OF_MONTH]);
tm->tm_mon = rtc_from_bcd(s, s->cmos_data[RTC_MONTH]) - 1;
tm->tm_year = rtc_from_bcd(s, s->cmos_data[RTC_YEAR]) + s->base_year - 1900;
rtc_change_mon_event(tm);
}
static void rtc_copy_date(RTCState *s)
{
const struct tm *tm = &s->current_tm;
int year;
s->cmos_data[RTC_SECONDS] = rtc_to_bcd(s, tm->tm_sec);
s->cmos_data[RTC_MINUTES] = rtc_to_bcd(s, tm->tm_min);
if (s->cmos_data[RTC_REG_B] & REG_B_24H) {
/* 24 hour format */
s->cmos_data[RTC_HOURS] = rtc_to_bcd(s, tm->tm_hour);
} else {
/* 12 hour format */
s->cmos_data[RTC_HOURS] = rtc_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] = rtc_to_bcd(s, tm->tm_wday + 1);
s->cmos_data[RTC_DAY_OF_MONTH] = rtc_to_bcd(s, tm->tm_mday);
s->cmos_data[RTC_MONTH] = rtc_to_bcd(s, tm->tm_mon + 1);
year = (tm->tm_year - s->base_year) % 100;
if (year < 0)
year += 100;
s->cmos_data[RTC_YEAR] = rtc_to_bcd(s, year);
}
/* 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 += get_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 = (get_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 ||
rtc_from_bcd(s, s->cmos_data[RTC_SECONDS_ALARM]) == s->current_tm.tm_sec) &&
((s->cmos_data[RTC_MINUTES_ALARM] & 0xc0) == 0xc0 ||
rtc_from_bcd(s, s->cmos_data[RTC_MINUTES_ALARM]) == s->current_tm.tm_min) &&
((s->cmos_data[RTC_HOURS_ALARM] & 0xc0) == 0xc0 ||
rtc_from_bcd(s, s->cmos_data[RTC_HOURS_ALARM]) == s->current_tm.tm_hour)) {
s->cmos_data[RTC_REG_C] |= 0xa0;
qemu_irq_raise(s->irq);
}
}
/* update ended interrupt */
s->cmos_data[RTC_REG_C] |= REG_C_UF;
if (s->cmos_data[RTC_REG_B] & REG_B_UIE) {
s->cmos_data[RTC_REG_C] |= REG_C_IRQF;
qemu_irq_raise(s->irq);
}
/* clear update in progress bit */
s->cmos_data[RTC_REG_A] &= ~REG_A_UIP;
s->next_second_time += get_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 &&
s->irq_reinject_on_ack_count < RTC_REINJECT_ON_ACK_COUNT) {
s->irq_reinject_on_ack_count++;
apic_reset_irq_delivered();
DPRINTF_C("cmos: injecting on ack\n");
qemu_irq_raise(s->irq);
if (apic_get_irq_delivered()) {
s->irq_coalesced--;
DPRINTF_C("cmos: coalesced irqs decreased to %d\n",
s->irq_coalesced);
}
break;
}
#endif
s->cmos_data[RTC_REG_C] = 0x00;
break;
default:
ret = s->cmos_data[s->cmos_index];
break;
}
CMOS_DPRINTF("cmos: read index=0x%02x val=0x%02x\n",
s->cmos_index, ret);
return ret;
}
}
void rtc_set_memory(ISADevice *dev, int addr, int val)
{
RTCState *s = DO_UPCAST(RTCState, dev, dev);
if (addr >= 0 && addr <= 127)
s->cmos_data[addr] = val;
}
void rtc_set_date(ISADevice *dev, const struct tm *tm)
{
RTCState *s = DO_UPCAST(RTCState, dev, dev);
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(ISADevice *dev)
{
RTCState *s = DO_UPCAST(RTCState, dev, dev);
struct tm tm;
int val;
/* set the CMOS date */
qemu_get_timedate(&tm, 0);
rtc_set_date(dev, &tm);
val = rtc_to_bcd(s, (tm.tm_year / 100) + 19);
rtc_set_memory(dev, REG_IBM_CENTURY_BYTE, val);
rtc_set_memory(dev, REG_IBM_PS2_CENTURY_BYTE, val);
}
static int rtc_post_load(void *opaque, int version_id)
{
#ifdef TARGET_I386
RTCState *s = opaque;
if (version_id >= 2) {
if (rtc_td_hack) {
rtc_coalesced_timer_update(s);
}
}
#endif
return 0;
}
static const VMStateDescription vmstate_rtc = {
.name = "mc146818rtc",
.version_id = 2,
.minimum_version_id = 1,
.minimum_version_id_old = 1,
.post_load = rtc_post_load,
.fields = (VMStateField []) {
VMSTATE_BUFFER(cmos_data, RTCState),
VMSTATE_UINT8(cmos_index, RTCState),
VMSTATE_INT32(current_tm.tm_sec, RTCState),
VMSTATE_INT32(current_tm.tm_min, RTCState),
VMSTATE_INT32(current_tm.tm_hour, RTCState),
VMSTATE_INT32(current_tm.tm_wday, RTCState),
VMSTATE_INT32(current_tm.tm_mday, RTCState),
VMSTATE_INT32(current_tm.tm_mon, RTCState),
VMSTATE_INT32(current_tm.tm_year, RTCState),
VMSTATE_TIMER(periodic_timer, RTCState),
VMSTATE_INT64(next_periodic_time, RTCState),
VMSTATE_INT64(next_second_time, RTCState),
VMSTATE_TIMER(second_timer, RTCState),
VMSTATE_TIMER(second_timer2, RTCState),
VMSTATE_UINT32_V(irq_coalesced, RTCState, 2),
VMSTATE_UINT32_V(period, RTCState, 2),
VMSTATE_END_OF_LIST()
}
};
static void rtc_reset(void *opaque)
{
RTCState *s = opaque;
s->cmos_data[RTC_REG_B] &= ~(REG_B_PIE | REG_B_AIE | REG_B_SQWE);
s->cmos_data[RTC_REG_C] &= ~(REG_C_UF | REG_C_IRQF | REG_C_PF | REG_C_AF);
qemu_irq_lower(s->irq);
#ifdef TARGET_I386
if (rtc_td_hack)
s->irq_coalesced = 0;
#endif
}
static int rtc_initfn(ISADevice *dev)
{
RTCState *s = DO_UPCAST(RTCState, dev, dev);
int base = 0x70;
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(dev);
s->periodic_timer = qemu_new_timer(rtc_clock, rtc_periodic_timer, s);
#ifdef TARGET_I386
if (rtc_td_hack)
s->coalesced_timer =
qemu_new_timer(rtc_clock, rtc_coalesced_timer, s);
#endif
s->second_timer = qemu_new_timer(rtc_clock, rtc_update_second, s);
s->second_timer2 = qemu_new_timer(rtc_clock, rtc_update_second2, s);
s->next_second_time =
qemu_get_clock(rtc_clock) + (get_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);
isa_init_ioport_range(dev, base, 2);
qdev_set_legacy_instance_id(&dev->qdev, base, 2);
qemu_register_reset(rtc_reset, s);
return 0;
}
ISADevice *rtc_init(int base_year, qemu_irq intercept_irq)
{
ISADevice *dev;
RTCState *s;
dev = isa_create("mc146818rtc");
s = DO_UPCAST(RTCState, dev, dev);
qdev_prop_set_int32(&dev->qdev, "base_year", base_year);
qdev_init_nofail(&dev->qdev);
if (intercept_irq) {
s->irq = intercept_irq;
} else {
isa_init_irq(dev, &s->irq, RTC_ISA_IRQ);
}
return dev;
}
static ISADeviceInfo mc146818rtc_info = {
.qdev.name = "mc146818rtc",
.qdev.size = sizeof(RTCState),
.qdev.no_user = 1,
.qdev.vmsd = &vmstate_rtc,
.init = rtc_initfn,
.qdev.props = (Property[]) {
DEFINE_PROP_INT32("base_year", RTCState, base_year, 1980),
DEFINE_PROP_END_OF_LIST(),
}
};
static void mc146818rtc_register(void)
{
isa_qdev_register(&mc146818rtc_info);
}
device_init(mc146818rtc_register)
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