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/*

 * QEMU Xilinx OPB Interrupt Controller.

 *

 * Copyright (c) 2009 Edgar E. Iglesias.

 *

 * 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 "hw/hw.h"

#define D(x)

#define R_ISR       0

#define R_IPR       1

#define R_IER       2

#define R_IAR       3

#define R_SIE       4

#define R_CIE       5

#define R_IVR       6

#define R_MER       7

#define R_MAX       8

struct xlx_pic

{

    SysBusDevice busdev;

    MemoryRegion mmio;

    qemu_irq parent_irq;

    /* Configuration reg chosen at synthesis-time. QEMU populates

       the bits at board-setup.  */

    uint32_t c_kind_of_intr;

    /* Runtime control registers.  */

    uint32_t regs[R_MAX];

    /* state of the interrupt input pins */

    uint32_t irq_pin_state;

};

static void update_irq(struct xlx_pic *p)

{

    uint32_t i;

    /* level triggered interrupt */

    if (p->regs[R_MER] & 2) {

        p->regs[R_ISR] |= p->irq_pin_state & ~p->c_kind_of_intr;

    }

    /* Update the pending register.  */

    p->regs[R_IPR] = p->regs[R_ISR] & p->regs[R_IER];

    /* Update the vector register.  */

    for (i = 0; i < 32; i++) {

        if (p->regs[R_IPR] & (1 << i))

            break;

    }

    if (i == 32)

        i = ~0;

    p->regs[R_IVR] = i;

    qemu_set_irq(p->parent_irq, (p->regs[R_MER] & 1) && p->regs[R_IPR]);

}

static uint64_t

pic_read(void *opaque, hwaddr addr, unsigned int size)

{

    struct xlx_pic *p = opaque;

    uint32_t r = 0;

    addr >>= 2;

    switch (addr)

    {

        default:

            if (addr < ARRAY_SIZE(p->regs))

                r = p->regs[addr];

            break;

    }

    D(printf("%s %x=%x\n", __func__, addr * 4, r));

    return r;

}

static void

pic_write(void *opaque, hwaddr addr,

          uint64_t val64, unsigned int size)

{

    struct xlx_pic *p = opaque;

    uint32_t value = val64;

    addr >>= 2;

    D(qemu_log("%s addr=%x val=%x\n", __func__, addr * 4, value));

    switch (addr) 

    {

        case R_IAR:

            p->regs[R_ISR] &= ~value; /* ACK.  */

            break;

        case R_SIE:

            p->regs[R_IER] |= value;  /* Atomic set ie.  */

            break;

        case R_CIE:

            p->regs[R_IER] &= ~value; /* Atomic clear ie.  */

            break;

        case R_ISR:

            if ((p->regs[R_MER] & 2)) {

                break;

            }

            /* fallthrough */

        default:

            if (addr < ARRAY_SIZE(p->regs))

                p->regs[addr] = value;

            break;

    }

    update_irq(p);

}

static const MemoryRegionOps pic_ops = {

    .read = pic_read,

    .write = pic_write,

    .endianness = DEVICE_NATIVE_ENDIAN,

    .valid = {

        .min_access_size = 4,

        .max_access_size = 4

    }

};

static void irq_handler(void *opaque, int irq, int level)

{

    struct xlx_pic *p = opaque;

    /* edge triggered interrupt */

    if (p->c_kind_of_intr & (1 << irq) && p->regs[R_MER] & 2) {

        p->regs[R_ISR] |= (level << irq);

    }

    p->irq_pin_state &= ~(1 << irq);

    p->irq_pin_state |= level << irq;

    update_irq(p);

}

static int xilinx_intc_init(SysBusDevice *dev)

{

    struct xlx_pic *p = FROM_SYSBUS(typeof (*p), dev);

    qdev_init_gpio_in(&dev->qdev, irq_handler, 32);

    sysbus_init_irq(dev, &p->parent_irq);

    memory_region_init_io(&p->mmio, &pic_ops, p, "xlnx.xps-intc", R_MAX * 4);

    sysbus_init_mmio(dev, &p->mmio);

    return 0;

}

static Property xilinx_intc_properties[] = {

    DEFINE_PROP_UINT32("kind-of-intr", struct xlx_pic, c_kind_of_intr, 0),

    DEFINE_PROP_END_OF_LIST(),

};

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

{

    DeviceClass *dc = DEVICE_CLASS(klass);

    SysBusDeviceClass *k = SYS_BUS_DEVICE_CLASS(klass);

    k->init = xilinx_intc_init;

    dc->props = xilinx_intc_properties;

}

static const TypeInfo xilinx_intc_info = {

    .name          = "xlnx.xps-intc",

    .parent        = TYPE_SYS_BUS_DEVICE,

    .instance_size = sizeof(struct xlx_pic),

    .class_init    = xilinx_intc_class_init,

};

static void xilinx_intc_register_types(void)

{

    type_register_static(&xilinx_intc_info);

}

type_init(xilinx_intc_register_types)