Archipelago » qemu

/*

 *  High Precisition Event Timer emulation

 *

 *  Copyright (c) 2007 Alexander Graf

 *  Copyright (c) 2008 IBM Corporation

 *

 *  Authors: Beth Kon <bkon@us.ibm.com>

 *

 * This library is free software; you can redistribute it and/or

 * modify it under the terms of the GNU Lesser General Public

 * License as published by the Free Software Foundation; either

 * version 2 of the License, or (at your option) any later version.

 *

 * This library is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

 * Lesser General Public License for more details.

 *

 * You should have received a copy of the GNU Lesser General Public

 * License along with this library; if not, see <http://www.gnu.org/licenses/>.

 *

 * *****************************************************************

 *

 * This driver attempts to emulate an HPET device in software.

 */

#include "hw.h"

#include "pc.h"

#include "console.h"

#include "qemu-timer.h"

#include "hpet_emul.h"

//#define HPET_DEBUG

#ifdef HPET_DEBUG

#define DPRINTF printf

#else

#define DPRINTF(...)

#endif

struct HPETState;

typedef struct HPETTimer {  /* timers */

    uint8_t tn;             /*timer number*/

    QEMUTimer *qemu_timer;

    struct HPETState *state;

    /* Memory-mapped, software visible timer registers */

    uint64_t config;        /* configuration/cap */

    uint64_t cmp;           /* comparator */

    uint64_t fsb;           /* FSB route, not supported now */

    /* Hidden register state */

    uint64_t period;        /* Last value written to comparator */

    uint8_t wrap_flag;      /* timer pop will indicate wrap for one-shot 32-bit

                             * mode. Next pop will be actual timer expiration.

                             */

} HPETTimer;

typedef struct HPETState {

    uint64_t hpet_offset;

    qemu_irq *irqs;

    HPETTimer timer[HPET_NUM_TIMERS];

    /* Memory-mapped, software visible registers */

    uint64_t capability;        /* capabilities */

    uint64_t config;            /* configuration */

    uint64_t isr;               /* interrupt status reg */

    uint64_t hpet_counter;      /* main counter */

} HPETState;

static HPETState *hpet_statep;

uint32_t hpet_in_legacy_mode(void)

{

    if (!hpet_statep) {

        return 0;

    }

    return hpet_statep->config & HPET_CFG_LEGACY;

}

static uint32_t timer_int_route(struct HPETTimer *timer)

{

    return (timer->config & HPET_TN_INT_ROUTE_MASK) >> HPET_TN_INT_ROUTE_SHIFT;

}

static uint32_t hpet_enabled(void)

{

    return hpet_statep->config & HPET_CFG_ENABLE;

}

static uint32_t timer_is_periodic(HPETTimer *t)

{

    return t->config & HPET_TN_PERIODIC;

}

static uint32_t timer_enabled(HPETTimer *t)

{

    return t->config & HPET_TN_ENABLE;

}

static uint32_t hpet_time_after(uint64_t a, uint64_t b)

{

    return ((int32_t)(b) - (int32_t)(a) < 0);

}

static uint32_t hpet_time_after64(uint64_t a, uint64_t b)

{

    return ((int64_t)(b) - (int64_t)(a) < 0);

}

static uint64_t ticks_to_ns(uint64_t value)

{

    return (muldiv64(value, HPET_CLK_PERIOD, FS_PER_NS));

}

static uint64_t ns_to_ticks(uint64_t value)

{

    return (muldiv64(value, FS_PER_NS, HPET_CLK_PERIOD));

}

static uint64_t hpet_fixup_reg(uint64_t new, uint64_t old, uint64_t mask)

{

    new &= mask;

    new |= old & ~mask;

    return new;

}

static int activating_bit(uint64_t old, uint64_t new, uint64_t mask)

{

    return (!(old & mask) && (new & mask));

}

static int deactivating_bit(uint64_t old, uint64_t new, uint64_t mask)

{

    return ((old & mask) && !(new & mask));

}

static uint64_t hpet_get_ticks(void)

{

    return ns_to_ticks(qemu_get_clock(vm_clock) + hpet_statep->hpet_offset);

}

/*

 * calculate diff between comparator value and current ticks

 */

static inline uint64_t hpet_calculate_diff(HPETTimer *t, uint64_t current)

{

    if (t->config & HPET_TN_32BIT) {

        uint32_t diff, cmp;

        cmp = (uint32_t)t->cmp;

        diff = cmp - (uint32_t)current;

        diff = (int32_t)diff > 0 ? diff : (uint32_t)0;

        return (uint64_t)diff;

    } else {

        uint64_t diff, cmp;

        cmp = t->cmp;

        diff = cmp - current;

        diff = (int64_t)diff > 0 ? diff : (uint64_t)0;

        return diff;

    }

}

static void update_irq(struct HPETTimer *timer)

{

    int route;

    if (timer->tn <= 1 && hpet_in_legacy_mode()) {

        /* if LegacyReplacementRoute bit is set, HPET specification requires

         * timer0 be routed to IRQ0 in NON-APIC or IRQ2 in the I/O APIC,

         * timer1 be routed to IRQ8 in NON-APIC or IRQ8 in the I/O APIC.

         */

        route = (timer->tn == 0) ? 0 : 8;

    } else {

        route = timer_int_route(timer);

    }

    if (!timer_enabled(timer) || !hpet_enabled()) {

        return;

    }

    qemu_irq_pulse(timer->state->irqs[route]);

}

static void hpet_pre_save(void *opaque)

{

    HPETState *s = opaque;

    /* save current counter value */

    s->hpet_counter = hpet_get_ticks();

}

static int hpet_post_load(void *opaque, int version_id)

{

    HPETState *s = opaque;

    /* Recalculate the offset between the main counter and guest time */

    s->hpet_offset = ticks_to_ns(s->hpet_counter) - qemu_get_clock(vm_clock);

    return 0;

}

static const VMStateDescription vmstate_hpet_timer = {

    .name = "hpet_timer",

    .version_id = 1,

    .minimum_version_id = 1,

    .minimum_version_id_old = 1,

    .fields      = (VMStateField []) {

        VMSTATE_UINT8(tn, HPETTimer),

        VMSTATE_UINT64(config, HPETTimer),

        VMSTATE_UINT64(cmp, HPETTimer),

        VMSTATE_UINT64(fsb, HPETTimer),

        VMSTATE_UINT64(period, HPETTimer),

        VMSTATE_UINT8(wrap_flag, HPETTimer),

        VMSTATE_TIMER(qemu_timer, HPETTimer),

        VMSTATE_END_OF_LIST()

    }

};

static const VMStateDescription vmstate_hpet = {

    .name = "hpet",

    .version_id = 1,

    .minimum_version_id = 1,

    .minimum_version_id_old = 1,

    .pre_save = hpet_pre_save,

    .post_load = hpet_post_load,

    .fields      = (VMStateField []) {

        VMSTATE_UINT64(config, HPETState),

        VMSTATE_UINT64(isr, HPETState),

        VMSTATE_UINT64(hpet_counter, HPETState),

        VMSTATE_STRUCT_ARRAY(timer, HPETState, HPET_NUM_TIMERS, 0,

                             vmstate_hpet_timer, HPETTimer),

        VMSTATE_END_OF_LIST()

    }

};

/*

 * timer expiration callback

 */

static void hpet_timer(void *opaque)

{

    HPETTimer *t = opaque;

    uint64_t diff;

    uint64_t period = t->period;

    uint64_t cur_tick = hpet_get_ticks();

    if (timer_is_periodic(t) && period != 0) {

        if (t->config & HPET_TN_32BIT) {

            while (hpet_time_after(cur_tick, t->cmp)) {

                t->cmp = (uint32_t)(t->cmp + t->period);

            }

        } else {

            while (hpet_time_after64(cur_tick, t->cmp)) {

                t->cmp += period;

            }

        }

        diff = hpet_calculate_diff(t, cur_tick);

        qemu_mod_timer(t->qemu_timer,

                       qemu_get_clock(vm_clock) + (int64_t)ticks_to_ns(diff));

    } else if (t->config & HPET_TN_32BIT && !timer_is_periodic(t)) {

        if (t->wrap_flag) {

            diff = hpet_calculate_diff(t, cur_tick);

            qemu_mod_timer(t->qemu_timer, qemu_get_clock(vm_clock) +

                           (int64_t)ticks_to_ns(diff));

            t->wrap_flag = 0;

        }

    }

    update_irq(t);

}

static void hpet_set_timer(HPETTimer *t)

{

    uint64_t diff;

    uint32_t wrap_diff;  /* how many ticks until we wrap? */

    uint64_t cur_tick = hpet_get_ticks();

    /* whenever new timer is being set up, make sure wrap_flag is 0 */

    t->wrap_flag = 0;

    diff = hpet_calculate_diff(t, cur_tick);

    /* hpet spec says in one-shot 32-bit mode, generate an interrupt when

     * counter wraps in addition to an interrupt with comparator match.

     */

    if (t->config & HPET_TN_32BIT && !timer_is_periodic(t)) {

        wrap_diff = 0xffffffff - (uint32_t)cur_tick;

        if (wrap_diff < (uint32_t)diff) {

            diff = wrap_diff;

            t->wrap_flag = 1;

        }

    }

    qemu_mod_timer(t->qemu_timer,

                   qemu_get_clock(vm_clock) + (int64_t)ticks_to_ns(diff));

}

static void hpet_del_timer(HPETTimer *t)

{

    qemu_del_timer(t->qemu_timer);

}

#ifdef HPET_DEBUG

static uint32_t hpet_ram_readb(void *opaque, target_phys_addr_t addr)

{

    printf("qemu: hpet_read b at %" PRIx64 "\n", addr);

    return 0;

}

static uint32_t hpet_ram_readw(void *opaque, target_phys_addr_t addr)

{

    printf("qemu: hpet_read w at %" PRIx64 "\n", addr);

    return 0;

}

#endif

static uint32_t hpet_ram_readl(void *opaque, target_phys_addr_t addr)

{

    HPETState *s = opaque;

    uint64_t cur_tick, index;

    DPRINTF("qemu: Enter hpet_ram_readl at %" PRIx64 "\n", addr);

    index = addr;

    /*address range of all TN regs*/

    if (index >= 0x100 && index <= 0x3ff) {

        uint8_t timer_id = (addr - 0x100) / 0x20;

        HPETTimer *timer = &s->timer[timer_id];

        if (timer_id > HPET_NUM_TIMERS - 1) {

            DPRINTF("qemu: timer id out of range\n");

            return 0;

        }

        switch ((addr - 0x100) % 0x20) {

        case HPET_TN_CFG:

            return timer->config;

        case HPET_TN_CFG + 4: // Interrupt capabilities

            return timer->config >> 32;

        case HPET_TN_CMP: // comparator register

            return timer->cmp;

        case HPET_TN_CMP + 4:

            return timer->cmp >> 32;

        case HPET_TN_ROUTE:

            return timer->fsb >> 32;

        default:

            DPRINTF("qemu: invalid hpet_ram_readl\n");

            break;

        }

    } else {

        switch (index) {

        case HPET_ID:

            return s->capability;

        case HPET_PERIOD:

            return s->capability >> 32;

        case HPET_CFG:

            return s->config;

        case HPET_CFG + 4:

            DPRINTF("qemu: invalid HPET_CFG + 4 hpet_ram_readl \n");

            return 0;

        case HPET_COUNTER:

            if (hpet_enabled()) {

                cur_tick = hpet_get_ticks();

            } else {

                cur_tick = s->hpet_counter;

            }

            DPRINTF("qemu: reading counter  = %" PRIx64 "\n", cur_tick);

            return cur_tick;

        case HPET_COUNTER + 4:

            if (hpet_enabled()) {

                cur_tick = hpet_get_ticks();

            } else {

                cur_tick = s->hpet_counter;

            }

            DPRINTF("qemu: reading counter + 4  = %" PRIx64 "\n", cur_tick);

            return cur_tick >> 32;

        case HPET_STATUS:

            return s->isr;

        default:

            DPRINTF("qemu: invalid hpet_ram_readl\n");

            break;

        }

    }

    return 0;

}

#ifdef HPET_DEBUG

static void hpet_ram_writeb(void *opaque, target_phys_addr_t addr,

                            uint32_t value)

{

    printf("qemu: invalid hpet_write b at %" PRIx64 " = %#x\n",

           addr, value);

}

static void hpet_ram_writew(void *opaque, target_phys_addr_t addr,

                            uint32_t value)

{

    printf("qemu: invalid hpet_write w at %" PRIx64 " = %#x\n",

           addr, value);

}

#endif

static void hpet_ram_writel(void *opaque, target_phys_addr_t addr,

                            uint32_t value)

{

    int i;

    HPETState *s = opaque;

    uint64_t old_val, new_val, val, index;

    DPRINTF("qemu: Enter hpet_ram_writel at %" PRIx64 " = %#x\n", addr, value);

    index = addr;

    old_val = hpet_ram_readl(opaque, addr);

    new_val = value;

    /*address range of all TN regs*/

    if (index >= 0x100 && index <= 0x3ff) {

        uint8_t timer_id = (addr - 0x100) / 0x20;

        HPETTimer *timer = &s->timer[timer_id];

        DPRINTF("qemu: hpet_ram_writel timer_id = %#x \n", timer_id);

        if (timer_id > HPET_NUM_TIMERS - 1) {

            DPRINTF("qemu: timer id out of range\n");

            return;

        }

        switch ((addr - 0x100) % 0x20) {

        case HPET_TN_CFG:

            DPRINTF("qemu: hpet_ram_writel HPET_TN_CFG\n");

            val = hpet_fixup_reg(new_val, old_val, HPET_TN_CFG_WRITE_MASK);

            timer->config = (timer->config & 0xffffffff00000000ULL) | val;

            if (new_val & HPET_TN_32BIT) {

                timer->cmp = (uint32_t)timer->cmp;

                timer->period = (uint32_t)timer->period;

            }

            if (new_val & HPET_TN_TYPE_LEVEL) {

                printf("qemu: level-triggered hpet not supported\n");

                exit (-1);

            }

            break;

        case HPET_TN_CFG + 4: // Interrupt capabilities

            DPRINTF("qemu: invalid HPET_TN_CFG+4 write\n");

            break;

        case HPET_TN_CMP: // comparator register

            DPRINTF("qemu: hpet_ram_writel HPET_TN_CMP \n");

            if (timer->config & HPET_TN_32BIT) {

                new_val = (uint32_t)new_val;

            }

            if (!timer_is_periodic(timer)

                || (timer->config & HPET_TN_SETVAL)) {

                timer->cmp = (timer->cmp & 0xffffffff00000000ULL) | new_val;

            }

            if (timer_is_periodic(timer)) {

                /*

                 * FIXME: Clamp period to reasonable min value?

                 * Clamp period to reasonable max value

                 */

                new_val &= (timer->config & HPET_TN_32BIT ? ~0u : ~0ull) >> 1;

                timer->period =

                    (timer->period & 0xffffffff00000000ULL) | new_val;

            }

            timer->config &= ~HPET_TN_SETVAL;

            if (hpet_enabled()) {

                hpet_set_timer(timer);

            }

            break;

        case HPET_TN_CMP + 4: // comparator register high order

            DPRINTF("qemu: hpet_ram_writel HPET_TN_CMP + 4\n");

            if (!timer_is_periodic(timer)

                || (timer->config & HPET_TN_SETVAL)) {

                timer->cmp = (timer->cmp & 0xffffffffULL) | new_val << 32;

            } else {

                /*

                 * FIXME: Clamp period to reasonable min value?

                 * Clamp period to reasonable max value

                 */

                new_val &= (timer->config & HPET_TN_32BIT ? ~0u : ~0ull) >> 1;

                timer->period =

                    (timer->period & 0xffffffffULL) | new_val << 32;

                }

                timer->config &= ~HPET_TN_SETVAL;

                if (hpet_enabled()) {

                    hpet_set_timer(timer);

                }

                break;

        case HPET_TN_ROUTE + 4:

            DPRINTF("qemu: hpet_ram_writel HPET_TN_ROUTE + 4\n");

            break;

        default:

            DPRINTF("qemu: invalid hpet_ram_writel\n");

            break;

        }

        return;

    } else {

        switch (index) {

        case HPET_ID:

            return;

        case HPET_CFG:

            val = hpet_fixup_reg(new_val, old_val, HPET_CFG_WRITE_MASK);

            s->config = (s->config & 0xffffffff00000000ULL) | val;

            if (activating_bit(old_val, new_val, HPET_CFG_ENABLE)) {

                /* Enable main counter and interrupt generation. */

                s->hpet_offset =

                    ticks_to_ns(s->hpet_counter) - qemu_get_clock(vm_clock);

                for (i = 0; i < HPET_NUM_TIMERS; i++) {

                    if ((&s->timer[i])->cmp != ~0ULL) {

                        hpet_set_timer(&s->timer[i]);

                    }

                }

            } else if (deactivating_bit(old_val, new_val, HPET_CFG_ENABLE)) {

                /* Halt main counter and disable interrupt generation. */

                s->hpet_counter = hpet_get_ticks();

                for (i = 0; i < HPET_NUM_TIMERS; i++) {

                    hpet_del_timer(&s->timer[i]);

                }

            }

            /* i8254 and RTC are disabled when HPET is in legacy mode */

            if (activating_bit(old_val, new_val, HPET_CFG_LEGACY)) {

                hpet_pit_disable();

            } else if (deactivating_bit(old_val, new_val, HPET_CFG_LEGACY)) {

                hpet_pit_enable();

            }

            break;

        case HPET_CFG + 4:

            DPRINTF("qemu: invalid HPET_CFG+4 write \n");

            break;

        case HPET_STATUS:

            /* FIXME: need to handle level-triggered interrupts */

            break;

        case HPET_COUNTER:

            if (hpet_enabled()) {

                printf("qemu: Writing counter while HPET enabled!\n");

            }

            s->hpet_counter =

                (s->hpet_counter & 0xffffffff00000000ULL) | value;

            DPRINTF("qemu: HPET counter written. ctr = %#x -> %" PRIx64 "\n",

                    value, s->hpet_counter);

            break;

        case HPET_COUNTER + 4:

            if (hpet_enabled()) {

                printf("qemu: Writing counter while HPET enabled!\n");

            }

            s->hpet_counter =

                (s->hpet_counter & 0xffffffffULL) | (((uint64_t)value) << 32);

            DPRINTF("qemu: HPET counter + 4 written. ctr = %#x -> %" PRIx64 "\n",

                    value, s->hpet_counter);

            break;

        default:

            DPRINTF("qemu: invalid hpet_ram_writel\n");

            break;

        }

    }

}

static CPUReadMemoryFunc * const hpet_ram_read[] = {

#ifdef HPET_DEBUG

    hpet_ram_readb,

    hpet_ram_readw,

#else

    NULL,

    NULL,

#endif

    hpet_ram_readl,

};

static CPUWriteMemoryFunc * const hpet_ram_write[] = {

#ifdef HPET_DEBUG

    hpet_ram_writeb,

    hpet_ram_writew,

#else

    NULL,

    NULL,

#endif

    hpet_ram_writel,

};

static void hpet_reset(void *opaque)

{

    HPETState *s = opaque;

    int i;

    static int count = 0;

    for (i = 0; i < HPET_NUM_TIMERS; i++) {

        HPETTimer *timer = &s->timer[i];

        hpet_del_timer(timer);

        timer->tn = i;

        timer->cmp = ~0ULL;

        timer->config =  HPET_TN_PERIODIC_CAP | HPET_TN_SIZE_CAP;

        /* advertise availability of ioapic inti2 */

        timer->config |=  0x00000004ULL << 32;

        timer->state = s;

        timer->period = 0ULL;

        timer->wrap_flag = 0;

    }

    s->hpet_counter = 0ULL;

    s->hpet_offset = 0ULL;

    /* 64-bit main counter; 3 timers supported; LegacyReplacementRoute. */

    s->capability = 0x8086a201ULL;

    s->capability |= ((HPET_CLK_PERIOD) << 32);

    s->config = 0ULL;

    if (count > 0) {

        /* we don't enable pit when hpet_reset is first called (by hpet_init)

         * because hpet is taking over for pit here. On subsequent invocations,

         * hpet_reset is called due to system reset. At this point control must

         * be returned to pit until SW reenables hpet.

         */

        hpet_pit_enable();

    }

    count = 1;

}

void hpet_init(qemu_irq *irq)

{

    int i, iomemtype;

    HPETTimer *timer;

    HPETState *s;

    DPRINTF ("hpet_init\n");

    s = qemu_mallocz(sizeof(HPETState));

    hpet_statep = s;

    s->irqs = irq;

    for (i = 0; i < HPET_NUM_TIMERS; i++) {

        timer = &s->timer[i];

        timer->qemu_timer = qemu_new_timer(vm_clock, hpet_timer, timer);

    }

    vmstate_register(-1, &vmstate_hpet, s);

    qemu_register_reset(hpet_reset, s);

    /* HPET Area */

    iomemtype = cpu_register_io_memory(hpet_ram_read,

                                       hpet_ram_write, s);

    cpu_register_physical_memory(HPET_BASE, 0x400, iomemtype);

}