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/*

 * QEMU Sparc SLAVIO timer controller emulation

 *

 * Copyright (c) 2003-2005 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 "sun4m.h"

#include "qemu-timer.h"

#include "sysbus.h"

//#define DEBUG_TIMER

#ifdef DEBUG_TIMER

#define DPRINTF(fmt, ...)                                       \

    do { printf("TIMER: " fmt , ## __VA_ARGS__); } while (0)

#else

#define DPRINTF(fmt, ...) do {} while (0)

#endif

/*

 * Registers of hardware timer in sun4m.

 *

 * This is the timer/counter part of chip STP2001 (Slave I/O), also

 * produced as NCR89C105. See

 * http://www.ibiblio.org/pub/historic-linux/early-ports/Sparc/NCR/NCR89C105.txt

 *

 * The 31-bit counter is incremented every 500ns by bit 9. Bits 8..0

 * are zero. Bit 31 is 1 when count has been reached.

 *

 * Per-CPU timers interrupt local CPU, system timer uses normal

 * interrupt routing.

 *

 */

#define MAX_CPUS 16

typedef struct CPUTimerState {

    qemu_irq irq;

    ptimer_state *timer;

    uint32_t count, counthigh, reached;

    uint64_t limit;

    // processor only

    uint32_t running;

} CPUTimerState;

typedef struct SLAVIO_TIMERState {

    SysBusDevice busdev;

    uint32_t num_cpus;

    CPUTimerState cputimer[MAX_CPUS + 1];

    uint32_t cputimer_mode;

} SLAVIO_TIMERState;

typedef struct TimerContext {

    SLAVIO_TIMERState *s;

    unsigned int timer_index; /* 0 for system, 1 ... MAX_CPUS for CPU timers */

} TimerContext;

#define SYS_TIMER_SIZE 0x14

#define CPU_TIMER_SIZE 0x10

#define TIMER_LIMIT         0

#define TIMER_COUNTER       1

#define TIMER_COUNTER_NORST 2

#define TIMER_STATUS        3

#define TIMER_MODE          4

#define TIMER_COUNT_MASK32 0xfffffe00

#define TIMER_LIMIT_MASK32 0x7fffffff

#define TIMER_MAX_COUNT64  0x7ffffffffffffe00ULL

#define TIMER_MAX_COUNT32  0x7ffffe00ULL

#define TIMER_REACHED      0x80000000

#define TIMER_PERIOD       500ULL // 500ns

#define LIMIT_TO_PERIODS(l) ((l) >> 9)

#define PERIODS_TO_LIMIT(l) ((l) << 9)

static int slavio_timer_is_user(TimerContext *tc)

{

    SLAVIO_TIMERState *s = tc->s;

    unsigned int timer_index = tc->timer_index;

    return timer_index != 0 && (s->cputimer_mode & (1 << (timer_index - 1)));

}

// Update count, set irq, update expire_time

// Convert from ptimer countdown units

static void slavio_timer_get_out(CPUTimerState *t)

{

    uint64_t count, limit;

    if (t->limit == 0) { /* free-run system or processor counter */

        limit = TIMER_MAX_COUNT32;

    } else {

        limit = t->limit;

    }

    count = limit - PERIODS_TO_LIMIT(ptimer_get_count(t->timer));

    DPRINTF("get_out: limit %" PRIx64 " count %x%08x\n", t->limit, t->counthigh,

            t->count);

    t->count = count & TIMER_COUNT_MASK32;

    t->counthigh = count >> 32;

}

// timer callback

static void slavio_timer_irq(void *opaque)

{

    TimerContext *tc = opaque;

    SLAVIO_TIMERState *s = tc->s;

    CPUTimerState *t = &s->cputimer[tc->timer_index];

    slavio_timer_get_out(t);

    DPRINTF("callback: count %x%08x\n", t->counthigh, t->count);

    t->reached = TIMER_REACHED;

    if (!slavio_timer_is_user(tc)) {

        qemu_irq_raise(t->irq);

    }

}

static uint32_t slavio_timer_mem_readl(void *opaque, target_phys_addr_t addr)

{

    TimerContext *tc = opaque;

    SLAVIO_TIMERState *s = tc->s;

    uint32_t saddr, ret;

    unsigned int timer_index = tc->timer_index;

    CPUTimerState *t = &s->cputimer[timer_index];

    saddr = addr >> 2;

    switch (saddr) {

    case TIMER_LIMIT:

        // read limit (system counter mode) or read most signifying

        // part of counter (user mode)

        if (slavio_timer_is_user(tc)) {

            // read user timer MSW

            slavio_timer_get_out(t);

            ret = t->counthigh | t->reached;

        } else {

            // read limit

            // clear irq

            qemu_irq_lower(t->irq);

            t->reached = 0;

            ret = t->limit & TIMER_LIMIT_MASK32;

        }

        break;

    case TIMER_COUNTER:

        // read counter and reached bit (system mode) or read lsbits

        // of counter (user mode)

        slavio_timer_get_out(t);

        if (slavio_timer_is_user(tc)) { // read user timer LSW

            ret = t->count & TIMER_MAX_COUNT64;

        } else { // read limit

            ret = (t->count & TIMER_MAX_COUNT32) |

                t->reached;

        }

        break;

    case TIMER_STATUS:

        // only available in processor counter/timer

        // read start/stop status

        if (timer_index > 0) {

            ret = t->running;

        } else {

            ret = 0;

        }

        break;

    case TIMER_MODE:

        // only available in system counter

        // read user/system mode

        ret = s->cputimer_mode;

        break;

    default:

        DPRINTF("invalid read address " TARGET_FMT_plx "\n", addr);

        ret = 0;

        break;

    }

    DPRINTF("read " TARGET_FMT_plx " = %08x\n", addr, ret);

    return ret;

}

static void slavio_timer_mem_writel(void *opaque, target_phys_addr_t addr,

                                    uint32_t val)

{

    TimerContext *tc = opaque;

    SLAVIO_TIMERState *s = tc->s;

    uint32_t saddr;

    unsigned int timer_index = tc->timer_index;

    CPUTimerState *t = &s->cputimer[timer_index];

    DPRINTF("write " TARGET_FMT_plx " %08x\n", addr, val);

    saddr = addr >> 2;

    switch (saddr) {

    case TIMER_LIMIT:

        if (slavio_timer_is_user(tc)) {

            uint64_t count;

            // set user counter MSW, reset counter

            t->limit = TIMER_MAX_COUNT64;

            t->counthigh = val & (TIMER_MAX_COUNT64 >> 32);

            t->reached = 0;

            count = ((uint64_t)t->counthigh << 32) | t->count;

            DPRINTF("processor %d user timer set to %016" PRIx64 "\n",

                    timer_index, count);

            ptimer_set_count(t->timer, LIMIT_TO_PERIODS(t->limit - count));

        } else {

            // set limit, reset counter

            qemu_irq_lower(t->irq);

            t->limit = val & TIMER_MAX_COUNT32;

            if (t->timer) {

                if (t->limit == 0) { /* free-run */

                    ptimer_set_limit(t->timer,

                                     LIMIT_TO_PERIODS(TIMER_MAX_COUNT32), 1);

                } else {

                    ptimer_set_limit(t->timer, LIMIT_TO_PERIODS(t->limit), 1);

                }

            }

        }

        break;

    case TIMER_COUNTER:

        if (slavio_timer_is_user(tc)) {

            uint64_t count;

            // set user counter LSW, reset counter

            t->limit = TIMER_MAX_COUNT64;

            t->count = val & TIMER_MAX_COUNT64;

            t->reached = 0;

            count = ((uint64_t)t->counthigh) << 32 | t->count;

            DPRINTF("processor %d user timer set to %016" PRIx64 "\n",

                    timer_index, count);

            ptimer_set_count(t->timer, LIMIT_TO_PERIODS(t->limit - count));

        } else

            DPRINTF("not user timer\n");

        break;

    case TIMER_COUNTER_NORST:

        // set limit without resetting counter

        t->limit = val & TIMER_MAX_COUNT32;

        if (t->limit == 0) { /* free-run */

            ptimer_set_limit(t->timer, LIMIT_TO_PERIODS(TIMER_MAX_COUNT32), 0);

        } else {

            ptimer_set_limit(t->timer, LIMIT_TO_PERIODS(t->limit), 0);

        }

        break;

    case TIMER_STATUS:

        if (slavio_timer_is_user(tc)) {

            // start/stop user counter

            if ((val & 1) && !t->running) {

                DPRINTF("processor %d user timer started\n",

                        timer_index);

                ptimer_run(t->timer, 0);

                t->running = 1;

            } else if (!(val & 1) && t->running) {

                DPRINTF("processor %d user timer stopped\n",

                        timer_index);

                ptimer_stop(t->timer);

                t->running = 0;

            }

        }

        break;

    case TIMER_MODE:

        if (timer_index == 0) {

            unsigned int i;

            for (i = 0; i < s->num_cpus; i++) {

                unsigned int processor = 1 << i;

                CPUTimerState *curr_timer = &s->cputimer[i + 1];

                // check for a change in timer mode for this processor

                if ((val & processor) != (s->cputimer_mode & processor)) {

                    if (val & processor) { // counter -> user timer

                        qemu_irq_lower(curr_timer->irq);

                        // counters are always running

                        ptimer_stop(curr_timer->timer);

                        curr_timer->running = 0;

                        // user timer limit is always the same

                        curr_timer->limit = TIMER_MAX_COUNT64;

                        ptimer_set_limit(curr_timer->timer,

                                         LIMIT_TO_PERIODS(curr_timer->limit),

                                         1);

                        // set this processors user timer bit in config

                        // register

                        s->cputimer_mode |= processor;

                        DPRINTF("processor %d changed from counter to user "

                                "timer\n", timer_index);

                    } else { // user timer -> counter

                        // stop the user timer if it is running

                        if (curr_timer->running) {

                            ptimer_stop(curr_timer->timer);

                        }

                        // start the counter

                        ptimer_run(curr_timer->timer, 0);

                        curr_timer->running = 1;

                        // clear this processors user timer bit in config

                        // register

                        s->cputimer_mode &= ~processor;

                        DPRINTF("processor %d changed from user timer to "

                                "counter\n", timer_index);

                    }

                }

            }

        } else {

            DPRINTF("not system timer\n");

        }

        break;

    default:

        DPRINTF("invalid write address " TARGET_FMT_plx "\n", addr);

        break;

    }

}

static CPUReadMemoryFunc * const slavio_timer_mem_read[3] = {

    NULL,

    NULL,

    slavio_timer_mem_readl,

};

static CPUWriteMemoryFunc * const slavio_timer_mem_write[3] = {

    NULL,

    NULL,

    slavio_timer_mem_writel,

};

static const VMStateDescription vmstate_timer = {

    .name ="timer",

    .version_id = 3,

    .minimum_version_id = 3,

    .minimum_version_id_old = 3,

    .fields      = (VMStateField []) {

        VMSTATE_UINT64(limit, CPUTimerState),

        VMSTATE_UINT32(count, CPUTimerState),

        VMSTATE_UINT32(counthigh, CPUTimerState),

        VMSTATE_UINT32(reached, CPUTimerState),

        VMSTATE_UINT32(running, CPUTimerState),

        VMSTATE_PTIMER(timer, CPUTimerState),

        VMSTATE_END_OF_LIST()

    }

};

static const VMStateDescription vmstate_slavio_timer = {

    .name ="slavio_timer",

    .version_id = 3,

    .minimum_version_id = 3,

    .minimum_version_id_old = 3,

    .fields      = (VMStateField []) {

        VMSTATE_STRUCT_ARRAY(cputimer, SLAVIO_TIMERState, MAX_CPUS + 1, 3,

                             vmstate_timer, CPUTimerState),

        VMSTATE_END_OF_LIST()

    }

};

static void slavio_timer_reset(void *opaque)

{

    SLAVIO_TIMERState *s = opaque;

    unsigned int i;

    CPUTimerState *curr_timer;

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

        curr_timer = &s->cputimer[i];

        curr_timer->limit = 0;

        curr_timer->count = 0;

        curr_timer->reached = 0;

        if (i < s->num_cpus) {

            ptimer_set_limit(curr_timer->timer,

                             LIMIT_TO_PERIODS(TIMER_MAX_COUNT32), 1);

            ptimer_run(curr_timer->timer, 0);

        }

        curr_timer->running = 1;

    }

    s->cputimer_mode = 0;

}

static int slavio_timer_init1(SysBusDevice *dev)

{

    int io;

    SLAVIO_TIMERState *s = FROM_SYSBUS(SLAVIO_TIMERState, dev);

    QEMUBH *bh;

    unsigned int i;

    TimerContext *tc;

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

        tc = qemu_mallocz(sizeof(TimerContext));

        tc->s = s;

        tc->timer_index = i;

        bh = qemu_bh_new(slavio_timer_irq, tc);

        s->cputimer[i].timer = ptimer_init(bh);

        ptimer_set_period(s->cputimer[i].timer, TIMER_PERIOD);

        io = cpu_register_io_memory(slavio_timer_mem_read,

                                    slavio_timer_mem_write, tc);

        if (i == 0) {

            sysbus_init_mmio(dev, SYS_TIMER_SIZE, io);

        } else {

            sysbus_init_mmio(dev, CPU_TIMER_SIZE, io);

        }

        sysbus_init_irq(dev, &s->cputimer[i].irq);

    }

    vmstate_register(-1, &vmstate_slavio_timer, s);

    qemu_register_reset(slavio_timer_reset, s);

    slavio_timer_reset(s);

    return 0;

}

static SysBusDeviceInfo slavio_timer_info = {

    .init = slavio_timer_init1,

    .qdev.name  = "slavio_timer",

    .qdev.size  = sizeof(SLAVIO_TIMERState),

    .qdev.props = (Property[]) {

        DEFINE_PROP_UINT32("num_cpus",  SLAVIO_TIMERState, num_cpus,  0),

        DEFINE_PROP_END_OF_LIST(),

    }

};

static void slavio_timer_register_devices(void)

{

    sysbus_register_withprop(&slavio_timer_info);

}

device_init(slavio_timer_register_devices)