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more precise RTC emulation (periodic timers + time updates)
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git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@688 c046a42c-6fe2-441c-8c8c-71466251a162
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bellard committed Mar 31, 2004
1 parent 1f1af9f commit dff38e7
Showing 1 changed file with 264 additions and 34 deletions.
298 changes: 264 additions & 34 deletions hw/mc146818rtc.c
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Original file line number Diff line number Diff line change
Expand Up @@ -63,11 +63,62 @@
#define RTC_REG_C 12
#define RTC_REG_D 13

/* PC cmos mappings */
#define REG_IBM_CENTURY_BYTE 0x32
#define REG_IBM_PS2_CENTURY_BYTE 0x37
#define REG_A_UIP 0x80

RTCState rtc_state;
#define REG_B_SET 0x80
#define REG_B_PIE 0x40
#define REG_B_AIE 0x20
#define REG_B_UIE 0x10

struct RTCState {
uint8_t cmos_data[128];
uint8_t cmos_index;
int current_time; /* in seconds */
int irq;
uint8_t buf_data[10]; /* buffered data */
/* periodic timer */
QEMUTimer *periodic_timer;
int64_t next_periodic_time;
/* second update */
int64_t next_second_time;
QEMUTimer *second_timer;
QEMUTimer *second_timer2;
};

static void rtc_set_time(RTCState *s);
static void rtc_set_date_buf(RTCState *s, const struct tm *tm);
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 (period_code != 0 &&
(s->cmos_data[RTC_REG_B] & REG_B_PIE)) {
if (period_code <= 2)
period_code += 7;
/* period in 32 Khz cycles */
period = 1 << (period_code - 1);
/* 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 {
qemu_del_timer(s->periodic_timer);
}
}

static void rtc_periodic_timer(void *opaque)
{
RTCState *s = opaque;

rtc_timer_update(s, s->next_periodic_time);
s->cmos_data[RTC_REG_C] |= 0xc0;
pic_set_irq(s->irq, 1);
}

static void cmos_ioport_write(void *opaque, uint32_t addr, uint32_t data)
{
Expand All @@ -80,7 +131,7 @@ static void cmos_ioport_write(void *opaque, uint32_t addr, uint32_t data)
printf("cmos: write index=0x%02x val=0x%02x\n",
s->cmos_index, data);
#endif
switch(addr) {
switch(s->cmos_index) {
case RTC_SECONDS_ALARM:
case RTC_MINUTES_ALARM:
case RTC_HOURS_ALARM:
Expand All @@ -95,10 +146,30 @@ static void cmos_ioport_write(void *opaque, uint32_t addr, uint32_t data)
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:
s->cmos_data[s->cmos_index] = data;
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:
Expand All @@ -111,27 +182,104 @@ static void cmos_ioport_write(void *opaque, uint32_t addr, uint32_t data)
}
}

static inline int to_bcd(int a)
static inline int to_bcd(RTCState *s, int a)
{
return ((a / 10) << 4) | (a % 10);
if (s->cmos_data[RTC_REG_B] & 0x04) {
return a;
} else {
return ((a / 10) << 4) | (a % 10);
}
}

static void cmos_update_time(RTCState *s)
static inline int from_bcd(RTCState *s, int a)
{
struct tm *tm;
if (s->cmos_data[RTC_REG_B] & 0x04) {
return a;
} else {
return ((a >> 4) * 10) + (a & 0x0f);
}
}

static void rtc_set_time(RTCState *s)
{
struct tm tm1, *tm = &tm1;

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]);
tm->tm_wday = from_bcd(s, s->cmos_data[RTC_DAY_OF_WEEK]);
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;

/* update internal state */
s->buf_data[RTC_SECONDS] = s->cmos_data[RTC_SECONDS];
s->buf_data[RTC_MINUTES] = s->cmos_data[RTC_MINUTES];
s->buf_data[RTC_HOURS] = s->cmos_data[RTC_HOURS];
s->buf_data[RTC_DAY_OF_WEEK] = s->cmos_data[RTC_DAY_OF_WEEK];
s->buf_data[RTC_DAY_OF_MONTH] = s->cmos_data[RTC_DAY_OF_MONTH];
s->buf_data[RTC_MONTH] = s->cmos_data[RTC_MONTH];
s->buf_data[RTC_YEAR] = s->cmos_data[RTC_YEAR];
s->current_time = mktime(tm);
}

static void rtc_update_second(void *opaque)
{
RTCState *s = opaque;

/* 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 {
s->current_time++;

if (!(s->cmos_data[RTC_REG_B] & REG_B_SET)) {
/* update in progress bit */
s->cmos_data[RTC_REG_A] |= REG_A_UIP;
}
qemu_mod_timer(s->second_timer2,
s->next_second_time + (ticks_per_sec * 99) / 100);
}
}

static void rtc_update_second2(void *opaque)
{
RTCState *s = opaque;
time_t ti;

ti = time(NULL);
tm = gmtime(&ti);
s->cmos_data[RTC_SECONDS] = to_bcd(tm->tm_sec);
s->cmos_data[RTC_MINUTES] = to_bcd(tm->tm_min);
s->cmos_data[RTC_HOURS] = to_bcd(tm->tm_hour);
s->cmos_data[RTC_DAY_OF_WEEK] = to_bcd(tm->tm_wday);
s->cmos_data[RTC_DAY_OF_MONTH] = to_bcd(tm->tm_mday);
s->cmos_data[RTC_MONTH] = to_bcd(tm->tm_mon + 1);
s->cmos_data[RTC_YEAR] = to_bcd(tm->tm_year % 100);
s->cmos_data[REG_IBM_CENTURY_BYTE] = to_bcd((tm->tm_year / 100) + 19);
s->cmos_data[REG_IBM_PS2_CENTURY_BYTE] = s->cmos_data[REG_IBM_CENTURY_BYTE];
ti = s->current_time;
rtc_set_date_buf(s, gmtime(&ti));

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->buf_data[RTC_SECONDS]) &&
((s->cmos_data[RTC_MINUTES_ALARM] & 0xc0) == 0xc0 ||
s->cmos_data[RTC_MINUTES_ALARM] == s->buf_data[RTC_MINUTES]) &&
((s->cmos_data[RTC_HOURS_ALARM] & 0xc0) == 0xc0 ||
s->cmos_data[RTC_HOURS_ALARM] == s->buf_data[RTC_HOURS])) {

s->cmos_data[RTC_REG_C] |= 0xa0;
pic_set_irq(s->irq, 1);
}
}

/* update ended interrupt */
if (s->cmos_data[RTC_REG_B] & REG_B_UIE) {
s->cmos_data[RTC_REG_C] |= 0x90;
pic_set_irq(s->irq, 1);
}

/* 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)
Expand All @@ -149,16 +297,10 @@ static uint32_t cmos_ioport_read(void *opaque, uint32_t addr)
case RTC_DAY_OF_MONTH:
case RTC_MONTH:
case RTC_YEAR:
case REG_IBM_CENTURY_BYTE:
case REG_IBM_PS2_CENTURY_BYTE:
cmos_update_time(s);
ret = s->cmos_data[s->cmos_index];
break;
case RTC_REG_A:
ret = s->cmos_data[s->cmos_index];
/* toggle update-in-progress bit for Linux (same hack as
plex86) */
s->cmos_data[RTC_REG_A] ^= 0x80;
break;
case RTC_REG_C:
ret = s->cmos_data[s->cmos_index];
Expand All @@ -177,27 +319,115 @@ static uint32_t cmos_ioport_read(void *opaque, uint32_t addr)
}
}

void rtc_timer(void)
static void rtc_set_date_buf(RTCState *s, const struct tm *tm)
{
RTCState *s = &rtc_state;
if (s->cmos_data[RTC_REG_B] & 0x50) {
pic_set_irq(s->irq, 1);
s->buf_data[RTC_SECONDS] = to_bcd(s, tm->tm_sec);
s->buf_data[RTC_MINUTES] = to_bcd(s, tm->tm_min);
if (s->cmos_data[RTC_REG_B] & 0x02) {
/* 24 hour format */
s->buf_data[RTC_HOURS] = to_bcd(s, tm->tm_hour);
} else {
/* 12 hour format */
s->buf_data[RTC_HOURS] = to_bcd(s, tm->tm_hour % 12);
if (tm->tm_hour >= 12)
s->buf_data[RTC_HOURS] |= 0x80;
}
s->buf_data[RTC_DAY_OF_WEEK] = to_bcd(s, tm->tm_wday);
s->buf_data[RTC_DAY_OF_MONTH] = to_bcd(s, tm->tm_mday);
s->buf_data[RTC_MONTH] = to_bcd(s, tm->tm_mon + 1);
s->buf_data[RTC_YEAR] = to_bcd(s, tm->tm_year % 100);
}

static void rtc_copy_date(RTCState *s)
{
s->cmos_data[RTC_SECONDS] = s->buf_data[RTC_SECONDS];
s->cmos_data[RTC_MINUTES] = s->buf_data[RTC_MINUTES];
s->cmos_data[RTC_HOURS] = s->buf_data[RTC_HOURS];
s->cmos_data[RTC_DAY_OF_WEEK] = s->buf_data[RTC_DAY_OF_WEEK];
s->cmos_data[RTC_DAY_OF_MONTH] = s->buf_data[RTC_DAY_OF_MONTH];
s->cmos_data[RTC_MONTH] = s->buf_data[RTC_MONTH];
s->cmos_data[RTC_YEAR] = s->buf_data[RTC_YEAR];
}

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_time = mktime((struct tm *)tm);
rtc_set_date_buf(s, tm);
rtc_copy_date(s);
}

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_be32s(f, &s->current_time);
qemu_put_buffer(f, s->buf_data, 10);

qemu_put_timer(f, s->periodic_timer);
qemu_put_be64s(f, &s->next_periodic_time);

qemu_put_be64s(f, &s->next_second_time);
qemu_put_timer(f, s->second_timer);
qemu_put_timer(f, s->second_timer2);
}

void rtc_init(int base, int irq)
static int rtc_load(QEMUFile *f, void *opaque, int version_id)
{
RTCState *s = &rtc_state;
RTCState *s = opaque;

if (version_id != 1)
return -EINVAL;

cmos_update_time(s);
qemu_get_buffer(f, s->cmos_data, 128);
qemu_get_8s(f, &s->cmos_index);
qemu_get_be32s(f, &s->current_time);
qemu_get_buffer(f, s->buf_data, 10);

qemu_get_timer(f, s->periodic_timer);
qemu_get_be64s(f, &s->next_periodic_time);

qemu_get_be64s(f, &s->next_second_time);
qemu_get_timer(f, s->second_timer);
qemu_get_timer(f, s->second_timer2);
return 0;
}

RTCState *rtc_init(int base, int 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;

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);
return s;
}

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