/*
 *  ioapic.c IOAPIC emulation logic
 *
 *  Copyright (c) 2004-2005 Fabrice Bellard
 *
 *  Split the ioapic logic from apic.c
 *  Xiantao Zhang <xiantao.zhang@intel.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., 51 Franklin Street, Fifth Floor, Boston MA  02110-1301 USA
 */

#include "hw/hw.h"
#include "hw/i386/pc.h"
#include "qemu/timer.h"
#include "qemu/host-utils.h"

//#define DEBUG_IOAPIC

#define IOAPIC_NUM_PINS			0x18
#define IOAPIC_LVT_MASKED 		(1<<16)

#define IOAPIC_TRIGGER_EDGE		0
#define IOAPIC_TRIGGER_LEVEL		1

/*io{apic,sapic} delivery mode*/
#define IOAPIC_DM_FIXED			0x0
#define IOAPIC_DM_LOWEST_PRIORITY	0x1
#define IOAPIC_DM_PMI			0x2
#define IOAPIC_DM_NMI			0x4
#define IOAPIC_DM_INIT			0x5
#define IOAPIC_DM_SIPI			0x5
#define IOAPIC_DM_EXTINT		0x7

struct IOAPICState {
    uint8_t id;
    uint8_t ioregsel;

    uint32_t irr;
    uint64_t ioredtbl[IOAPIC_NUM_PINS];
};

static void ioapic_service(IOAPICState *s)
{
    uint8_t i;
    uint8_t trig_mode;
    uint8_t vector;
    uint8_t delivery_mode;
    uint32_t mask;
    uint64_t entry;
    uint8_t dest;
    uint8_t dest_mode;
    uint8_t polarity;

    for (i = 0; i < IOAPIC_NUM_PINS; i++) {
        mask = 1 << i;
        if (s->irr & mask) {
            entry = s->ioredtbl[i];
            if (!(entry & IOAPIC_LVT_MASKED)) {
                trig_mode = ((entry >> 15) & 1);
                dest = entry >> 56;
                dest_mode = (entry >> 11) & 1;
                delivery_mode = (entry >> 8) & 7;
                polarity = (entry >> 13) & 1;
                if (trig_mode == IOAPIC_TRIGGER_EDGE)
                    s->irr &= ~mask;
                if (delivery_mode == IOAPIC_DM_EXTINT)
                    vector = pic_read_irq(isa_pic);
                else
                    vector = entry & 0xff;

                apic_deliver_irq(dest, dest_mode, delivery_mode,
                                 vector, polarity, trig_mode);
            }
        }
    }
}

void ioapic_set_irq(void *opaque, int vector, int level)
{
    IOAPICState *s = opaque;

    /* ISA IRQs map to GSI 1-1 except for IRQ0 which maps
     * to GSI 2.  GSI maps to ioapic 1-1.  This is not
     * the cleanest way of doing it but it should work. */

    if (vector == 0)
        vector = 2;

    if (vector >= 0 && vector < IOAPIC_NUM_PINS) {
        uint32_t mask = 1 << vector;
        uint64_t entry = s->ioredtbl[vector];

        if ((entry >> 15) & 1) {
            /* level triggered */
            if (level) {
                s->irr |= mask;
                ioapic_service(s);
            } else {
                s->irr &= ~mask;
            }
        } else {
            /* edge triggered */
            if (level) {
                s->irr |= mask;
                ioapic_service(s);
            }
        }
    }
}

static uint32_t ioapic_mem_readl(void *opaque, hwaddr addr)
{
    IOAPICState *s = opaque;
    int index;
    uint32_t val = 0;

    addr &= 0xff;
    if (addr == 0x00) {
        val = s->ioregsel;
    } else if (addr == 0x10) {
        switch (s->ioregsel) {
            case 0x00:
                val = s->id << 24;
                break;
            case 0x01:
                val = 0x11 | ((IOAPIC_NUM_PINS - 1) << 16); /* version 0x11 */
                break;
            case 0x02:
                val = 0;
                break;
            default:
                index = (s->ioregsel - 0x10) >> 1;
                if (index >= 0 && index < IOAPIC_NUM_PINS) {
                    if (s->ioregsel & 1)
                        val = s->ioredtbl[index] >> 32;
                    else
                        val = s->ioredtbl[index] & 0xffffffff;
                }
        }
#ifdef DEBUG_IOAPIC
        printf("I/O APIC read: %08x = %08x\n", s->ioregsel, val);
#endif
    }
    return val;
}

static void ioapic_mem_writel(void *opaque, hwaddr addr, uint32_t val)
{
    IOAPICState *s = opaque;
    int index;

    addr &= 0xff;
    if (addr == 0x00)  {
        s->ioregsel = val;
        return;
    } else if (addr == 0x10) {
#ifdef DEBUG_IOAPIC
        printf("I/O APIC write: %08x = %08x\n", s->ioregsel, val);
#endif
        switch (s->ioregsel) {
            case 0x00:
                s->id = (val >> 24) & 0xff;
                return;
            case 0x01:
            case 0x02:
                return;
            default:
                index = (s->ioregsel - 0x10) >> 1;
                if (index >= 0 && index < IOAPIC_NUM_PINS) {
                    if (s->ioregsel & 1) {
                        s->ioredtbl[index] &= 0xffffffff;
                        s->ioredtbl[index] |= (uint64_t)val << 32;
                    } else {
                        s->ioredtbl[index] &= ~0xffffffffULL;
                        s->ioredtbl[index] |= val;
                    }
                    ioapic_service(s);
                }
        }
    }
}

static const VMStateDescription vmstate_ioapic = {
    .name = "ioapic",
    .version_id = 1,
    .minimum_version_id = 1,
    .fields = (VMStateField []) {
        VMSTATE_UINT8(id, IOAPICState),
        VMSTATE_UINT8(ioregsel, IOAPICState),
        VMSTATE_UINT64_ARRAY(ioredtbl, IOAPICState, IOAPIC_NUM_PINS),
        VMSTATE_END_OF_LIST()
    }
};

static void ioapic_reset(void *opaque)
{
    IOAPICState *s = opaque;
    int i;

    memset(s, 0, sizeof(*s));
    for(i = 0; i < IOAPIC_NUM_PINS; i++)
        s->ioredtbl[i] = 1 << 16; /* mask LVT */
}

static CPUReadMemoryFunc *ioapic_mem_read[3] = {
    ioapic_mem_readl,
    ioapic_mem_readl,
    ioapic_mem_readl,
};

static CPUWriteMemoryFunc *ioapic_mem_write[3] = {
    ioapic_mem_writel,
    ioapic_mem_writel,
    ioapic_mem_writel,
};

IOAPICState *ioapic_init(void)
{
    IOAPICState *s;
    int io_memory;

    s = g_malloc0(sizeof(IOAPICState));
    ioapic_reset(s);

    io_memory = cpu_register_io_memory(ioapic_mem_read,
                                       ioapic_mem_write, s);
    cpu_register_physical_memory(0xfec00000, 0x1000, io_memory);

    vmstate_register(NULL, 0, &vmstate_ioapic, s);
    qemu_register_reset(ioapic_reset, s);

    return s;
}