Archipelago » qemu

/*

 * ColdFire Interrupt Controller emulation.

 *

 * Copyright (c) 2007 CodeSourcery.

 *

 * This code is licensed under the GPL

 */

#include "hw/hw.h"

#include "hw/m68k/mcf.h"

#include "exec/address-spaces.h"

typedef struct {

    MemoryRegion iomem;

    uint64_t ipr;

    uint64_t imr;

    uint64_t ifr;

    uint64_t enabled;

    uint8_t icr[64];

    M68kCPU *cpu;

    int active_vector;

} mcf_intc_state;

static void mcf_intc_update(mcf_intc_state *s)

{

    uint64_t active;

    int i;

    int best;

    int best_level;

    active = (s->ipr | s->ifr) & s->enabled & ~s->imr;

    best_level = 0;

    best = 64;

    if (active) {

        for (i = 0; i < 64; i++) {

            if ((active & 1) != 0 && s->icr[i] >= best_level) {

                best_level = s->icr[i];

                best = i;

            }

            active >>= 1;

        }

    }

    s->active_vector = ((best == 64) ? 24 : (best + 64));

    m68k_set_irq_level(s->cpu, best_level, s->active_vector);

}

static uint64_t mcf_intc_read(void *opaque, hwaddr addr,

                              unsigned size)

{

    int offset;

    mcf_intc_state *s = (mcf_intc_state *)opaque;

    offset = addr & 0xff;

    if (offset >= 0x40 && offset < 0x80) {

        return s->icr[offset - 0x40];

    }

    switch (offset) {

    case 0x00:

        return (uint32_t)(s->ipr >> 32);

    case 0x04:

        return (uint32_t)s->ipr;

    case 0x08:

        return (uint32_t)(s->imr >> 32);

    case 0x0c:

        return (uint32_t)s->imr;

    case 0x10:

        return (uint32_t)(s->ifr >> 32);

    case 0x14:

        return (uint32_t)s->ifr;

    case 0xe0: /* SWIACK.  */

        return s->active_vector;

    case 0xe1: case 0xe2: case 0xe3: case 0xe4:

    case 0xe5: case 0xe6: case 0xe7:

        /* LnIACK */

        hw_error("mcf_intc_read: LnIACK not implemented\n");

    default:

        return 0;

    }

}

static void mcf_intc_write(void *opaque, hwaddr addr,

                           uint64_t val, unsigned size)

{

    int offset;

    mcf_intc_state *s = (mcf_intc_state *)opaque;

    offset = addr & 0xff;

    if (offset >= 0x40 && offset < 0x80) {

        int n = offset - 0x40;

        s->icr[n] = val;

        if (val == 0)

            s->enabled &= ~(1ull << n);

        else

            s->enabled |= (1ull << n);

        mcf_intc_update(s);

        return;

    }

    switch (offset) {

    case 0x00: case 0x04:

        /* Ignore IPR writes.  */

        return;

    case 0x08:

        s->imr = (s->imr & 0xffffffff) | ((uint64_t)val << 32);

        break;

    case 0x0c:

        s->imr = (s->imr & 0xffffffff00000000ull) | (uint32_t)val;

        break;

    default:

        hw_error("mcf_intc_write: Bad write offset %d\n", offset);

        break;

    }

    mcf_intc_update(s);

}

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

{

    mcf_intc_state *s = (mcf_intc_state *)opaque;

    if (irq >= 64)

        return;

    if (level)

        s->ipr |= 1ull << irq;

    else

        s->ipr &= ~(1ull << irq);

    mcf_intc_update(s);

}

static void mcf_intc_reset(mcf_intc_state *s)

{

    s->imr = ~0ull;

    s->ipr = 0;

    s->ifr = 0;

    s->enabled = 0;

    memset(s->icr, 0, 64);

    s->active_vector = 24;

}

static const MemoryRegionOps mcf_intc_ops = {

    .read = mcf_intc_read,

    .write = mcf_intc_write,

    .endianness = DEVICE_NATIVE_ENDIAN,

};

qemu_irq *mcf_intc_init(MemoryRegion *sysmem,

                        hwaddr base,

                        M68kCPU *cpu)

{

    mcf_intc_state *s;

    s = g_malloc0(sizeof(mcf_intc_state));

    s->cpu = cpu;

    mcf_intc_reset(s);

    memory_region_init_io(&s->iomem, &mcf_intc_ops, s, "mcf", 0x100);

    memory_region_add_subregion(sysmem, base, &s->iomem);

    return qemu_allocate_irqs(mcf_intc_set_irq, s, 64);

}