Archipelago » qemu

/*

 * 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_ns(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_ns(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_ns(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_ns(rtc_clock, rtc_periodic_timer, s);

#ifdef TARGET_I386

    if (rtc_td_hack)

        s->coalesced_timer =

            qemu_new_timer_ns(rtc_clock, rtc_coalesced_timer, s);

#endif

    s->second_timer = qemu_new_timer_ns(rtc_clock, rtc_update_second, s);

    s->second_timer2 = qemu_new_timer_ns(rtc_clock, rtc_update_second2, s);

    s->next_second_time =

        qemu_get_clock_ns(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)