/*

 *  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, write to the Free Software

 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

 *

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

 *

 * 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

static HPETState *hpet_statep;

uint32_t hpet_in_legacy_mode(void)

{

    if (hpet_statep)

        return hpet_statep->config & HPET_CFG_LEGACY;

    else

        return 0;

}

static uint32_t timer_int_route(struct HPETTimer *timer)

{

    uint32_t route;

    route = (timer->config & HPET_TN_INT_ROUTE_MASK) >> HPET_TN_INT_ROUTE_SHIFT;

    return route;

}

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)

{

    uint64_t ticks;

    ticks = ns_to_ticks(qemu_get_clock(vm_clock) + hpet_statep->hpet_offset);

    return ticks;

}

/*

 * 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)

{

    qemu_irq irq;

    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.

         */

        if (timer->tn == 0) {

            irq=timer->state->irqs[0];

        } else

            irq=timer->state->irqs[8];

    } else {

        route=timer_int_route(timer);

        irq=timer->state->irqs[route];

    }

    if (timer_enabled(timer) && hpet_enabled()) {

        qemu_irq_pulse(irq);

    }

}

static void hpet_save(QEMUFile *f, void *opaque)

{

    HPETState *s = opaque;

    int i;

    qemu_put_be64s(f, &s->config);

    qemu_put_be64s(f, &s->isr);

    /* save current counter value */

    s->hpet_counter = hpet_get_ticks();

    qemu_put_be64s(f, &s->hpet_counter);

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

        qemu_put_8s(f, &s->timer[i].tn);

        qemu_put_be64s(f, &s->timer[i].config);

        qemu_put_be64s(f, &s->timer[i].cmp);

        qemu_put_be64s(f, &s->timer[i].fsb);

        qemu_put_be64s(f, &s->timer[i].period);

        qemu_put_8s(f, &s->timer[i].wrap_flag);

        if (s->timer[i].qemu_timer) {

            qemu_put_timer(f, s->timer[i].qemu_timer);

        }

    }

}

static int hpet_load(QEMUFile *f, void *opaque, int version_id)

{

    HPETState *s = opaque;

    int i;

    if (version_id != 1)

        return -EINVAL;

    qemu_get_be64s(f, &s->config);

    qemu_get_be64s(f, &s->isr);

    qemu_get_be64s(f, &s->hpet_counter);

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

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

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

        qemu_get_8s(f, &s->timer[i].tn);

        qemu_get_be64s(f, &s->timer[i].config);

        qemu_get_be64s(f, &s->timer[i].cmp);

        qemu_get_be64s(f, &s->timer[i].fsb);

        qemu_get_be64s(f, &s->timer[i].period);

        qemu_get_8s(f, &s->timer[i].wrap_flag);

        if (s->timer[i].qemu_timer) {

            qemu_get_timer(f, s->timer[i].qemu_timer);

        }

    }

    return 0;

}

/*

 * timer expiration callback

 */

static void hpet_timer(void *opaque)

{

    HPETTimer *t = (HPETTimer*)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 = (HPETState *)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;

        if (timer_id > HPET_NUM_TIMERS - 1) {

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

            return 0;

        }

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

        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 = (HPETState *)opaque;

    uint64_t old_val, new_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;

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

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

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

            case HPET_TN_CFG:

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

                timer->config = hpet_fixup_reg(new_val, old_val, 0x3e4e);

                if (new_val & HPET_TN_32BIT) {

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

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

                }

                if (new_val & HPET_TIMER_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;

                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 & 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:

                s->config = hpet_fixup_reg(new_val, old_val, 0x3);

                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 *hpet_ram_read[] = {

#ifdef HPET_DEBUG

    hpet_ram_readb,

    hpet_ram_readw,

#else

    NULL,

    NULL,

#endif

    hpet_ram_readl,

};

static CPUWriteMemoryFunc *hpet_ram_write[] = {

#ifdef HPET_DEBUG

    hpet_ram_writeb,

    hpet_ram_writew,

#else

    NULL,

    NULL,

#endif