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/*

 * OSTimer device simulation in PKUnity SoC

 *

 * Copyright (C) 2010-2012 Guan Xuetao

 *

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

 * it under the terms of the GNU General Public License version 2 as

 * published by the Free Software Foundation, or any later version.

 * See the COPYING file in the top-level directory.

 */

#include "hw/sysbus.h"

#include "hw/ptimer.h"

#include "qemu/main-loop.h"

#undef DEBUG_PUV3

#include "hw/unicore32/puv3.h"

#define TYPE_PUV3_OST "puv3_ost"

#define PUV3_OST(obj) OBJECT_CHECK(PUV3OSTState, (obj), TYPE_PUV3_OST)

/* puv3 ostimer implementation. */

typedef struct PUV3OSTState {

    SysBusDevice parent_obj;

    MemoryRegion iomem;

    QEMUBH *bh;

    qemu_irq irq;

    ptimer_state *ptimer;

    uint32_t reg_OSMR0;

    uint32_t reg_OSCR;

    uint32_t reg_OSSR;

    uint32_t reg_OIER;

} PUV3OSTState;

static uint64_t puv3_ost_read(void *opaque, hwaddr offset,

        unsigned size)

{

    PUV3OSTState *s = opaque;

    uint32_t ret = 0;

    switch (offset) {

    case 0x10: /* Counter Register */

        ret = s->reg_OSMR0 - (uint32_t)ptimer_get_count(s->ptimer);

        break;

    case 0x14: /* Status Register */

        ret = s->reg_OSSR;

        break;

    case 0x1c: /* Interrupt Enable Register */

        ret = s->reg_OIER;

        break;

    default:

        DPRINTF("Bad offset %x\n", (int)offset);

    }

    DPRINTF("offset 0x%x, value 0x%x\n", offset, ret);

    return ret;

}

static void puv3_ost_write(void *opaque, hwaddr offset,

        uint64_t value, unsigned size)

{

    PUV3OSTState *s = opaque;

    DPRINTF("offset 0x%x, value 0x%x\n", offset, value);

    switch (offset) {

    case 0x00: /* Match Register 0 */

        s->reg_OSMR0 = value;

        if (s->reg_OSMR0 > s->reg_OSCR) {

            ptimer_set_count(s->ptimer, s->reg_OSMR0 - s->reg_OSCR);

        } else {

            ptimer_set_count(s->ptimer, s->reg_OSMR0 +

                    (0xffffffff - s->reg_OSCR));

        }

        ptimer_run(s->ptimer, 2);

        break;

    case 0x14: /* Status Register */

        assert(value == 0);

        if (s->reg_OSSR) {

            s->reg_OSSR = value;

            qemu_irq_lower(s->irq);

        }

        break;

    case 0x1c: /* Interrupt Enable Register */

        s->reg_OIER = value;

        break;

    default:

        DPRINTF("Bad offset %x\n", (int)offset);

    }

}

static const MemoryRegionOps puv3_ost_ops = {

    .read = puv3_ost_read,

    .write = puv3_ost_write,

    .impl = {

        .min_access_size = 4,

        .max_access_size = 4,

    },

    .endianness = DEVICE_NATIVE_ENDIAN,

};

static void puv3_ost_tick(void *opaque)

{

    PUV3OSTState *s = opaque;

    DPRINTF("ost hit when ptimer counter from 0x%x to 0x%x!\n",

            s->reg_OSCR, s->reg_OSMR0);

    s->reg_OSCR = s->reg_OSMR0;

    if (s->reg_OIER) {

        s->reg_OSSR = 1;

        qemu_irq_raise(s->irq);

    }

}

static int puv3_ost_init(SysBusDevice *dev)

{

    PUV3OSTState *s = PUV3_OST(dev);

    s->reg_OIER = 0;

    s->reg_OSSR = 0;

    s->reg_OSMR0 = 0;

    s->reg_OSCR = 0;

    sysbus_init_irq(dev, &s->irq);

    s->bh = qemu_bh_new(puv3_ost_tick, s);

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

    ptimer_set_freq(s->ptimer, 50 * 1000 * 1000);

    memory_region_init_io(&s->iomem, OBJECT(s), &puv3_ost_ops, s, "puv3_ost",

            PUV3_REGS_OFFSET);

    sysbus_init_mmio(dev, &s->iomem);

    return 0;

}

static void puv3_ost_class_init(ObjectClass *klass, void *data)

{

    SysBusDeviceClass *sdc = SYS_BUS_DEVICE_CLASS(klass);

    sdc->init = puv3_ost_init;

}

static const TypeInfo puv3_ost_info = {

    .name = TYPE_PUV3_OST,

    .parent = TYPE_SYS_BUS_DEVICE,

    .instance_size = sizeof(PUV3OSTState),

    .class_init = puv3_ost_class_init,

};

static void puv3_ost_register_type(void)

{

    type_register_static(&puv3_ost_info);

}

type_init(puv3_ost_register_type)