/*
 * QEMU sun4v Real Time Clock device
 *
 * The sun4v_rtc device (sun4v tod clock)
 *
 * Copyright (c) 2016 Artyom Tarasenko
 *
 * This code is licensed under the GNU GPL v3 or (at your option) any later
 * version.
 */

#include "qemu/osdep.h"
#include "hw/hw.h"
#include "hw/sysbus.h"
#include "qemu/timer.h"
#include "hw/timer/sun4v-rtc.h"

//#define DEBUG_SUN4V_RTC

#ifdef DEBUG_SUN4V_RTC
#define DPRINTF(fmt, ...)                                       \
    do { printf("sun4v_rtc: " fmt , ## __VA_ARGS__); } while (0)
#else
#define DPRINTF(fmt, ...) do {} while (0)
#endif

#define TYPE_SUN4V_RTC "sun4v_rtc"
#define SUN4V_RTC(obj) OBJECT_CHECK(Sun4vRtc, (obj), TYPE_SUN4V_RTC)

typedef struct Sun4vRtc {
    SysBusDevice parent_obj;

    MemoryRegion iomem;
} Sun4vRtc;

static uint64_t sun4v_rtc_read(void *opaque, hwaddr addr,
                                unsigned size)
{
    uint64_t val = get_clock_realtime() / NANOSECONDS_PER_SECOND;
    if (!(addr & 4ULL)) {
        /* accessing the high 32 bits */
        val >>= 32;
    }
    DPRINTF("read from " TARGET_FMT_plx " val %lx\n", addr, val);
    return val;
}

static void sun4v_rtc_write(void *opaque, hwaddr addr,
                             uint64_t val, unsigned size)
{
    DPRINTF("write 0x%x to " TARGET_FMT_plx "\n", (unsigned)val, addr);
}

static const MemoryRegionOps sun4v_rtc_ops = {
    .read = sun4v_rtc_read,
    .write = sun4v_rtc_write,
    .endianness = DEVICE_NATIVE_ENDIAN,
};

void sun4v_rtc_init(hwaddr addr)
{
    DeviceState *dev;
    SysBusDevice *s;

    dev = qdev_create(NULL, TYPE_SUN4V_RTC);
    s = SYS_BUS_DEVICE(dev);

    qdev_init_nofail(dev);

    sysbus_mmio_map(s, 0, addr);
}

static int sun4v_rtc_init1(SysBusDevice *dev)
{
    Sun4vRtc *s = SUN4V_RTC(dev);

    memory_region_init_io(&s->iomem, OBJECT(s), &sun4v_rtc_ops, s,
                          "sun4v-rtc", 0x08ULL);
    sysbus_init_mmio(dev, &s->iomem);
    return 0;
}

static void sun4v_rtc_class_init(ObjectClass *klass, void *data)
{
    SysBusDeviceClass *k = SYS_BUS_DEVICE_CLASS(klass);

    k->init = sun4v_rtc_init1;
}

static const TypeInfo sun4v_rtc_info = {
    .name          = TYPE_SUN4V_RTC,
    .parent        = TYPE_SYS_BUS_DEVICE,
    .instance_size = sizeof(Sun4vRtc),
    .class_init    = sun4v_rtc_class_init,
};

static void sun4v_rtc_register_types(void)
{
    type_register_static(&sun4v_rtc_info);
}

type_init(sun4v_rtc_register_types)