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/*

 * QEMU GRLIB GPTimer Emulator

 *

 * Copyright (c) 2010-2011 AdaCore

 *

 * 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/sysbus.h"

#include "qemu/timer.h"

#include "hw/ptimer.h"

#include "trace.h"

#define UNIT_REG_SIZE    16     /* Size of memory mapped regs for the unit */

#define GPTIMER_REG_SIZE 16     /* Size of memory mapped regs for a GPTimer */

#define GPTIMER_MAX_TIMERS 8

/* GPTimer Config register fields */

#define GPTIMER_ENABLE      (1 << 0)

#define GPTIMER_RESTART     (1 << 1)

#define GPTIMER_LOAD        (1 << 2)

#define GPTIMER_INT_ENABLE  (1 << 3)

#define GPTIMER_INT_PENDING (1 << 4)

#define GPTIMER_CHAIN       (1 << 5) /* Not supported */

#define GPTIMER_DEBUG_HALT  (1 << 6) /* Not supported */

/* Memory mapped register offsets */

#define SCALER_OFFSET         0x00

#define SCALER_RELOAD_OFFSET  0x04

#define CONFIG_OFFSET         0x08

#define COUNTER_OFFSET        0x00

#define COUNTER_RELOAD_OFFSET 0x04

#define TIMER_BASE            0x10

typedef struct GPTimer     GPTimer;

typedef struct GPTimerUnit GPTimerUnit;

struct GPTimer {

    QEMUBH *bh;

    struct ptimer_state *ptimer;

    qemu_irq     irq;

    int          id;

    GPTimerUnit *unit;

    /* registers */

    uint32_t counter;

    uint32_t reload;

    uint32_t config;

};

struct GPTimerUnit {

    SysBusDevice  busdev;

    MemoryRegion iomem;

    uint32_t nr_timers;         /* Number of timers available */

    uint32_t freq_hz;           /* System frequency */

    uint32_t irq_line;          /* Base irq line */

    GPTimer *timers;

    /* registers */

    uint32_t scaler;

    uint32_t reload;

    uint32_t config;

};

static void grlib_gptimer_enable(GPTimer *timer)

{

    assert(timer != NULL);

    ptimer_stop(timer->ptimer);

    if (!(timer->config & GPTIMER_ENABLE)) {

        /* Timer disabled */

        trace_grlib_gptimer_disabled(timer->id, timer->config);

        return;

    }

    /* ptimer is triggered when the counter reach 0 but GPTimer is triggered at

       underflow. Set count + 1 to simulate the GPTimer behavior. */

    trace_grlib_gptimer_enable(timer->id, timer->counter + 1);

    ptimer_set_count(timer->ptimer, timer->counter + 1);

    ptimer_run(timer->ptimer, 1);

}

static void grlib_gptimer_restart(GPTimer *timer)

{

    assert(timer != NULL);

    trace_grlib_gptimer_restart(timer->id, timer->reload);

    timer->counter = timer->reload;

    grlib_gptimer_enable(timer);

}

static void grlib_gptimer_set_scaler(GPTimerUnit *unit, uint32_t scaler)

{

    int i = 0;

    uint32_t value = 0;

    assert(unit != NULL);

    if (scaler > 0) {

        value = unit->freq_hz / (scaler + 1);

    } else {

        value = unit->freq_hz;

    }

    trace_grlib_gptimer_set_scaler(scaler, value);

    for (i = 0; i < unit->nr_timers; i++) {

        ptimer_set_freq(unit->timers[i].ptimer, value);

    }

}

static void grlib_gptimer_hit(void *opaque)

{

    GPTimer *timer = opaque;

    assert(timer != NULL);

    trace_grlib_gptimer_hit(timer->id);

    /* Timer expired */

    if (timer->config & GPTIMER_INT_ENABLE) {

        /* Set the pending bit (only unset by write in the config register) */

        timer->config |= GPTIMER_INT_PENDING;

        qemu_irq_pulse(timer->irq);

    }

    if (timer->config & GPTIMER_RESTART) {

        grlib_gptimer_restart(timer);

    }

}

static uint64_t grlib_gptimer_read(void *opaque, hwaddr addr,

                                   unsigned size)

{

    GPTimerUnit        *unit  = opaque;

    hwaddr  timer_addr;

    int                 id;

    uint32_t            value = 0;

    addr &= 0xff;

    /* Unit registers */

    switch (addr) {

    case SCALER_OFFSET:

        trace_grlib_gptimer_readl(-1, addr, unit->scaler);

        return unit->scaler;

    case SCALER_RELOAD_OFFSET:

        trace_grlib_gptimer_readl(-1, addr, unit->reload);

        return unit->reload;

    case CONFIG_OFFSET:

        trace_grlib_gptimer_readl(-1, addr, unit->config);

        return unit->config;

    default:

        break;

    }

    timer_addr = (addr % TIMER_BASE);

    id         = (addr - TIMER_BASE) / TIMER_BASE;

    if (id >= 0 && id < unit->nr_timers) {

        /* GPTimer registers */

        switch (timer_addr) {

        case COUNTER_OFFSET:

            value = ptimer_get_count(unit->timers[id].ptimer);

            trace_grlib_gptimer_readl(id, addr, value);

            return value;

        case COUNTER_RELOAD_OFFSET:

            value = unit->timers[id].reload;

            trace_grlib_gptimer_readl(id, addr, value);

            return value;

        case CONFIG_OFFSET:

            trace_grlib_gptimer_readl(id, addr, unit->timers[id].config);

            return unit->timers[id].config;

        default:

            break;

        }

    }

    trace_grlib_gptimer_readl(-1, addr, 0);

    return 0;

}

static void grlib_gptimer_write(void *opaque, hwaddr addr,

                                uint64_t value, unsigned size)

{

    GPTimerUnit        *unit = opaque;

    hwaddr  timer_addr;

    int                 id;

    addr &= 0xff;

    /* Unit registers */

    switch (addr) {

    case SCALER_OFFSET:

        value &= 0xFFFF; /* clean up the value */

        unit->scaler = value;

        trace_grlib_gptimer_writel(-1, addr, unit->scaler);

        return;

    case SCALER_RELOAD_OFFSET:

        value &= 0xFFFF; /* clean up the value */

        unit->reload = value;

        trace_grlib_gptimer_writel(-1, addr, unit->reload);

        grlib_gptimer_set_scaler(unit, value);

        return;

    case CONFIG_OFFSET:

        /* Read Only (disable timer freeze not supported) */

        trace_grlib_gptimer_writel(-1, addr, 0);

        return;

    default:

        break;

    }

    timer_addr = (addr % TIMER_BASE);

    id         = (addr - TIMER_BASE) / TIMER_BASE;

    if (id >= 0 && id < unit->nr_timers) {

        /* GPTimer registers */

        switch (timer_addr) {

        case COUNTER_OFFSET:

            trace_grlib_gptimer_writel(id, addr, value);

            unit->timers[id].counter = value;

            grlib_gptimer_enable(&unit->timers[id]);

            return;

        case COUNTER_RELOAD_OFFSET:

            trace_grlib_gptimer_writel(id, addr, value);

            unit->timers[id].reload = value;

            return;

        case CONFIG_OFFSET:

            trace_grlib_gptimer_writel(id, addr, value);

            if (value & GPTIMER_INT_PENDING) {

                /* clear pending bit */

                value &= ~GPTIMER_INT_PENDING;

            } else {

                /* keep pending bit */

                value |= unit->timers[id].config & GPTIMER_INT_PENDING;

            }

            unit->timers[id].config = value;

            /* gptimer_restart calls gptimer_enable, so if "enable" and "load"

               bits are present, we just have to call restart. */

            if (value & GPTIMER_LOAD) {

                grlib_gptimer_restart(&unit->timers[id]);

            } else if (value & GPTIMER_ENABLE) {

                grlib_gptimer_enable(&unit->timers[id]);

            }

            /* These fields must always be read as 0 */

            value &= ~(GPTIMER_LOAD & GPTIMER_DEBUG_HALT);

            unit->timers[id].config = value;

            return;

        default:

            break;

        }

    }

    trace_grlib_gptimer_writel(-1, addr, value);

}

static const MemoryRegionOps grlib_gptimer_ops = {

    .read = grlib_gptimer_read,

    .write = grlib_gptimer_write,

    .endianness = DEVICE_NATIVE_ENDIAN,

    .valid = {

        .min_access_size = 4,

        .max_access_size = 4,

    },

};

static void grlib_gptimer_reset(DeviceState *d)

{

    GPTimerUnit *unit = container_of(d, GPTimerUnit, busdev.qdev);

    int          i    = 0;

    assert(unit != NULL);

    unit->scaler = 0;

    unit->reload = 0;

    unit->config = 0;

    unit->config  = unit->nr_timers;

    unit->config |= unit->irq_line << 3;

    unit->config |= 1 << 8;     /* separate interrupt */

    unit->config |= 1 << 9;     /* Disable timer freeze */

    for (i = 0; i < unit->nr_timers; i++) {

        GPTimer *timer = &unit->timers[i];

        timer->counter = 0;

        timer->reload = 0;

        timer->config = 0;

        ptimer_stop(timer->ptimer);

        ptimer_set_count(timer->ptimer, 0);

        ptimer_set_freq(timer->ptimer, unit->freq_hz);

    }

}

static int grlib_gptimer_init(SysBusDevice *dev)

{

    GPTimerUnit  *unit = FROM_SYSBUS(typeof(*unit), dev);

    unsigned int  i;

    assert(unit->nr_timers > 0);

    assert(unit->nr_timers <= GPTIMER_MAX_TIMERS);

    unit->timers = g_malloc0(sizeof unit->timers[0] * unit->nr_timers);

    for (i = 0; i < unit->nr_timers; i++) {

        GPTimer *timer = &unit->timers[i];

        timer->unit   = unit;

        timer->bh     = qemu_bh_new(grlib_gptimer_hit, timer);

        timer->ptimer = ptimer_init(timer->bh);

        timer->id     = i;

        /* One IRQ line for each timer */

        sysbus_init_irq(dev, &timer->irq);

        ptimer_set_freq(timer->ptimer, unit->freq_hz);

    }

    memory_region_init_io(&unit->iomem, &grlib_gptimer_ops, unit, "gptimer",

                          UNIT_REG_SIZE + GPTIMER_REG_SIZE * unit->nr_timers);

    sysbus_init_mmio(dev, &unit->iomem);

    return 0;

}

static Property grlib_gptimer_properties[] = {

    DEFINE_PROP_UINT32("frequency", GPTimerUnit, freq_hz,   40000000),

    DEFINE_PROP_UINT32("irq-line",  GPTimerUnit, irq_line,  8),

    DEFINE_PROP_UINT32("nr-timers", GPTimerUnit, nr_timers, 2),

    DEFINE_PROP_END_OF_LIST(),

};

static void grlib_gptimer_class_init(ObjectClass *klass, void *data)

{

    DeviceClass *dc = DEVICE_CLASS(klass);

    SysBusDeviceClass *k = SYS_BUS_DEVICE_CLASS(klass);

    k->init = grlib_gptimer_init;

    dc->reset = grlib_gptimer_reset;

    dc->props = grlib_gptimer_properties;

}

static const TypeInfo grlib_gptimer_info = {

    .name          = "grlib,gptimer",

    .parent        = TYPE_SYS_BUS_DEVICE,

    .instance_size = sizeof(GPTimerUnit),

    .class_init    = grlib_gptimer_class_init,

};

static void grlib_gptimer_register_types(void)

{

    type_register_static(&grlib_gptimer_info);

}

type_init(grlib_gptimer_register_types)