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/* 

 * ARM AMBA Generic/Distributed Interrupt Controller

 *

 * Copyright (c) 2006 CodeSourcery.

 * Written by Paul Brook

 *

 * This code is licenced under the GPL.

 */

/* TODO: Some variants of this controller can handle multiple CPUs.

   Currently only single CPU operation is implemented.  */

#include "vl.h"

#include "arm_pic.h"

//#define DEBUG_GIC

#ifdef DEBUG_GIC

#define DPRINTF(fmt, args...) \

do { printf("arm_gic: " fmt , ##args); } while (0)

#else

#define DPRINTF(fmt, args...) do {} while(0)

#endif

/* Distributed interrupt controller.  */

static const uint8_t gic_id[] =

{ 0x90, 0x13, 0x04, 0x00, 0x0d, 0xf0, 0x05, 0xb1 };

#define GIC_NIRQ 96

typedef struct gic_irq_state

{

    unsigned enabled:1;

    unsigned pending:1;

    unsigned active:1;

    unsigned level:1;

    unsigned model:1; /* 0 = 1:N, 1 = N:N */

    unsigned trigger:1; /* nonzero = edge triggered.  */

} gic_irq_state;

#define GIC_SET_ENABLED(irq) s->irq_state[irq].enabled = 1

#define GIC_CLEAR_ENABLED(irq) s->irq_state[irq].enabled = 0

#define GIC_TEST_ENABLED(irq) s->irq_state[irq].enabled

#define GIC_SET_PENDING(irq) s->irq_state[irq].pending = 1

#define GIC_CLEAR_PENDING(irq) s->irq_state[irq].pending = 0

#define GIC_TEST_PENDING(irq) s->irq_state[irq].pending

#define GIC_SET_ACTIVE(irq) s->irq_state[irq].active = 1

#define GIC_CLEAR_ACTIVE(irq) s->irq_state[irq].active = 0

#define GIC_TEST_ACTIVE(irq) s->irq_state[irq].active

#define GIC_SET_MODEL(irq) s->irq_state[irq].model = 1

#define GIC_CLEAR_MODEL(irq) s->irq_state[irq].model = 0

#define GIC_TEST_MODEL(irq) s->irq_state[irq].model

#define GIC_SET_LEVEL(irq) s->irq_state[irq].level = 1

#define GIC_CLEAR_LEVEL(irq) s->irq_state[irq].level = 0

#define GIC_TEST_LEVEL(irq) s->irq_state[irq].level

#define GIC_SET_TRIGGER(irq) s->irq_state[irq].trigger = 1

#define GIC_CLEAR_TRIGGER(irq) s->irq_state[irq].trigger = 0

#define GIC_TEST_TRIGGER(irq) s->irq_state[irq].trigger

typedef struct gic_state

{

    arm_pic_handler handler;

    uint32_t base;

    void *parent;

    int parent_irq;

    int enabled;

    int cpu_enabled;

    gic_irq_state irq_state[GIC_NIRQ];

    int irq_target[GIC_NIRQ];

    int priority[GIC_NIRQ];

    int last_active[GIC_NIRQ];

    int priority_mask;

    int running_irq;

    int running_priority;

    int current_pending;

} gic_state;

/* TODO: Many places that call this routine could be optimized.  */

/* Update interrupt status after enabled or pending bits have been changed.  */

static void gic_update(gic_state *s)

{

    int best_irq;

    int best_prio;

    int irq;

    s->current_pending = 1023;

    if (!s->enabled || !s->cpu_enabled) {

        pic_set_irq_new(s->parent, s->parent_irq, 0);

        return;

    }

    best_prio = 0x100;

    best_irq = 1023;

    for (irq = 0; irq < 96; irq++) {

        if (GIC_TEST_ENABLED(irq) && GIC_TEST_PENDING(irq)) {

            if (s->priority[irq] < best_prio) {

                best_prio = s->priority[irq];

                best_irq = irq;

            }

        }

    }

    if (best_prio > s->priority_mask) {

        pic_set_irq_new(s->parent, s->parent_irq, 0);

    } else {

        s->current_pending = best_irq;

        if (best_prio < s->running_priority) {

            DPRINTF("Raised pending IRQ %d\n", best_irq);

            pic_set_irq_new(s->parent, s->parent_irq, 1);

        }

    }

}

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

{

    gic_state *s = (gic_state *)opaque;

    /* The first external input line is internal interrupt 32.  */

    irq += 32;

    if (level == GIC_TEST_LEVEL(irq)) 

        return;

    if (level) {

        GIC_SET_LEVEL(irq);

        if (GIC_TEST_TRIGGER(irq) || GIC_TEST_ENABLED(irq)) {

            DPRINTF("Set %d pending\n", irq);

            GIC_SET_PENDING(irq);

        }

    } else {

        GIC_CLEAR_LEVEL(irq);

    }

    gic_update(s);

}

static void gic_set_running_irq(gic_state *s, int irq)

{

    s->running_irq = irq;

    if (irq == 1023)

        s->running_priority = 0x100;

    else

        s->running_priority = s->priority[irq];

    gic_update(s);

}

static uint32_t gic_acknowledge_irq(gic_state *s)

{

    int new_irq;

    new_irq = s->current_pending;

    if (new_irq == 1023 || s->priority[new_irq] >= s->running_priority) {

        DPRINTF("ACK no pending IRQ\n");

        return 1023;

    }

    pic_set_irq_new(s->parent, s->parent_irq, 0);

    s->last_active[new_irq] = s->running_irq;

    /* For level triggered interrupts we clear the pending bit while

       the interrupt is active.  */

    GIC_CLEAR_PENDING(new_irq);

    gic_set_running_irq(s, new_irq);

    DPRINTF("ACK %d\n", new_irq);

    return new_irq;

}

static void gic_complete_irq(gic_state * s, int irq)

{

    int update = 0;

    DPRINTF("EOI %d\n", irq);

    if (s->running_irq == 1023)

        return; /* No active IRQ.  */

    if (irq != 1023) {

        /* Mark level triggered interrupts as pending if they are still

           raised.  */

        if (!GIC_TEST_TRIGGER(irq) && GIC_TEST_ENABLED(irq)

                && GIC_TEST_LEVEL(irq)) {

            GIC_SET_PENDING(irq);

            update = 1;

        }

    }

    if (irq != s->running_irq) {

        /* Complete an IRQ that is not currently running.  */

        int tmp = s->running_irq;

        while (s->last_active[tmp] != 1023) {

            if (s->last_active[tmp] == irq) {

                s->last_active[tmp] = s->last_active[irq];

                break;

            }

            tmp = s->last_active[tmp];

        }

        if (update) {

            gic_update(s);

        }

    } else {

        /* Complete the current running IRQ.  */

        gic_set_running_irq(s, s->last_active[s->running_irq]);

    }

}

static uint32_t gic_dist_readb(void *opaque, target_phys_addr_t offset)

{

    gic_state *s = (gic_state *)opaque;

    uint32_t res;

    int irq;

    int i;

    offset -= s->base + 0x1000;

    if (offset < 0x100) {

        if (offset == 0)

            return s->enabled;

        if (offset == 4)

            return (GIC_NIRQ / 32) - 1;

        if (offset < 0x08)

            return 0;

        goto bad_reg;

    } else if (offset < 0x200) {

        /* Interrupt Set/Clear Enable.  */

        if (offset < 0x180)

            irq = (offset - 0x100) * 8;

        else

            irq = (offset - 0x180) * 8;

        if (irq >= GIC_NIRQ)

            goto bad_reg;

        res = 0;

        for (i = 0; i < 8; i++) {

            if (GIC_TEST_ENABLED(irq + i)) {

                res |= (1 << i);

            }

        }

    } else if (offset < 0x300) {

        /* Interrupt Set/Clear Pending.  */

        if (offset < 0x280)

            irq = (offset - 0x200) * 8;

        else

            irq = (offset - 0x280) * 8;

        if (irq >= GIC_NIRQ)

            goto bad_reg;

        res = 0;

        for (i = 0; i < 8; i++) {

            if (GIC_TEST_PENDING(irq + i)) {

                res |= (1 << i);

            }

        }

    } else if (offset < 0x400) {

        /* Interrupt Active.  */

        irq = (offset - 0x300) * 8;

        if (irq >= GIC_NIRQ)

            goto bad_reg;

        res = 0;

        for (i = 0; i < 8; i++) {

            if (GIC_TEST_ACTIVE(irq + i)) {

                res |= (1 << i);

            }

        }

    } else if (offset < 0x800) {

        /* Interrupt Priority.  */

        irq = offset - 0x400;

        if (irq >= GIC_NIRQ)

            goto bad_reg;

        res = s->priority[irq];

    } else if (offset < 0xc00) {

        /* Interrupt CPU Target.  */

        irq = offset - 0x800;

        if (irq >= GIC_NIRQ)

            goto bad_reg;

        res = s->irq_target[irq];

    } else if (offset < 0xf00) {

        /* Interrupt Configuration.  */

        irq = (offset - 0xc00) * 2;

        if (irq >= GIC_NIRQ)

            goto bad_reg;

        res = 0;

        for (i = 0; i < 4; i++) {

            if (GIC_TEST_MODEL(irq + i))

                res |= (1 << (i * 2));

            if (GIC_TEST_TRIGGER(irq + i))

                res |= (2 << (i * 2));

        }

    } else if (offset < 0xfe0) {

        goto bad_reg;

    } else /* offset >= 0xfe0 */ {

        if (offset & 3) {

            res = 0;

        } else {

            res = gic_id[(offset - 0xfe0) >> 2];

        }

    }

    return res;

bad_reg:

    cpu_abort (cpu_single_env, "gic_dist_readb: Bad offset %x\n", offset);

    return 0;

}

static uint32_t gic_dist_readw(void *opaque, target_phys_addr_t offset)

{

    uint32_t val;

    val = gic_dist_readb(opaque, offset);

    val |= gic_dist_readb(opaque, offset + 1) << 8;

    return val;

}

static uint32_t gic_dist_readl(void *opaque, target_phys_addr_t offset)

{

    uint32_t val;

    val = gic_dist_readw(opaque, offset);

    val |= gic_dist_readw(opaque, offset + 2) << 16;

    return val;

}

static void gic_dist_writeb(void *opaque, target_phys_addr_t offset,

                            uint32_t value)

{

    gic_state *s = (gic_state *)opaque;

    int irq;

    int i;

    offset -= s->base + 0x1000;

    if (offset < 0x100) {

        if (offset == 0) {

            s->enabled = (value & 1);

            DPRINTF("Distribution %sabled\n", s->enabled ? "En" : "Dis");

        } else if (offset < 4) {

            /* ignored.  */

        } else {

            goto bad_reg;

        }

    } else if (offset < 0x180) {

        /* Interrupt Set Enable.  */

        irq = (offset - 0x100) * 8;

        if (irq >= GIC_NIRQ)

            goto bad_reg;

        for (i = 0; i < 8; i++) {

            if (value & (1 << i)) {

                if (!GIC_TEST_ENABLED(irq + i))

                    DPRINTF("Enabled IRQ %d\n", irq + i);

                GIC_SET_ENABLED(irq + i);

                /* If a raised level triggered IRQ enabled then mark

                   is as pending.  */

                if (GIC_TEST_LEVEL(irq + i) && !GIC_TEST_TRIGGER(irq + i))

                    GIC_SET_PENDING(irq + i);

            }

        }

    } else if (offset < 0x200) {

        /* Interrupt Clear Enable.  */

        irq = (offset - 0x180) * 8;

        if (irq >= GIC_NIRQ)

            goto bad_reg;

        for (i = 0; i < 8; i++) {

            if (value & (1 << i)) {

                if (GIC_TEST_ENABLED(irq + i))

                    DPRINTF("Disabled IRQ %d\n", irq + i);

                GIC_CLEAR_ENABLED(irq + i);

            }

        }

    } else if (offset < 0x280) {

        /* Interrupt Set Pending.  */

        irq = (offset - 0x200) * 8;

        if (irq >= GIC_NIRQ)

            goto bad_reg;

        for (i = 0; i < 8; i++) {

            if (value & (1 << i)) {

                GIC_SET_PENDING(irq + i);

            }

        }

    } else if (offset < 0x300) {

        /* Interrupt Clear Pending.  */

        irq = (offset - 0x280) * 8;

        if (irq >= GIC_NIRQ)

            goto bad_reg;

        for (i = 0; i < 8; i++) {

            if (value & (1 << i)) {

                GIC_CLEAR_PENDING(irq + i);

            }

        }

    } else if (offset < 0x400) {

        /* Interrupt Active.  */

        goto bad_reg;

    } else if (offset < 0x800) {

        /* Interrupt Priority.  */

        irq = offset - 0x400;

        if (irq >= GIC_NIRQ)

            goto bad_reg;

        s->priority[irq] = value;

    } else if (offset < 0xc00) {

        /* Interrupt CPU Target.  */

        irq = offset - 0x800;

        if (irq >= GIC_NIRQ)

            goto bad_reg;

        s->irq_target[irq] = value;

    } else if (offset < 0xf00) {

        /* Interrupt Configuration.  */

        irq = (offset - 0xc00) * 4;

        if (irq >= GIC_NIRQ)

            goto bad_reg;

        for (i = 0; i < 4; i++) {

            if (value & (1 << (i * 2))) {

                GIC_SET_MODEL(irq + i);

            } else {

                GIC_CLEAR_MODEL(irq + i);

            }

            if (value & (2 << (i * 2))) {

                GIC_SET_TRIGGER(irq + i);

            } else {

                GIC_CLEAR_TRIGGER(irq + i);

            }

        }

    } else {

        /* 0xf00 is only handled for word writes.  */

        goto bad_reg;

    }

    gic_update(s);

    return;

bad_reg:

    cpu_abort (cpu_single_env, "gic_dist_writeb: Bad offset %x\n", offset);

}

static void gic_dist_writew(void *opaque, target_phys_addr_t offset,

                            uint32_t value)

{

    gic_state *s = (gic_state *)opaque;

    if (offset - s->base == 0xf00) {

        GIC_SET_PENDING(value & 0x3ff);

        gic_update(s);

        return;

    }

    gic_dist_writeb(opaque, offset, value & 0xff);

    gic_dist_writeb(opaque, offset + 1, value >> 8);

}

static void gic_dist_writel(void *opaque, target_phys_addr_t offset,

                            uint32_t value)

{

    gic_dist_writew(opaque, offset, value & 0xffff);

    gic_dist_writew(opaque, offset + 2, value >> 16);

}

static CPUReadMemoryFunc *gic_dist_readfn[] = {

   gic_dist_readb,

   gic_dist_readw,

   gic_dist_readl

};

static CPUWriteMemoryFunc *gic_dist_writefn[] = {

   gic_dist_writeb,

   gic_dist_writew,

   gic_dist_writel

};

static uint32_t gic_cpu_read(void *opaque, target_phys_addr_t offset)

{

    gic_state *s = (gic_state *)opaque;

    offset -= s->base;

    switch (offset) {

    case 0x00: /* Control */

        return s->cpu_enabled;

    case 0x04: /* Priority mask */

        return s->priority_mask;

    case 0x08: /* Binary Point */

        /* ??? Not implemented.  */

        return 0;

    case 0x0c: /* Acknowledge */

        return gic_acknowledge_irq(s);

    case 0x14: /* Runing Priority */

        return s->running_priority;

    case 0x18: /* Highest Pending Interrupt */

        return s->current_pending;

    default:

        cpu_abort (cpu_single_env, "gic_cpu_writeb: Bad offset %x\n", offset);

        return 0;

    }

}

static void gic_cpu_write(void *opaque, target_phys_addr_t offset,

                          uint32_t value)

{

    gic_state *s = (gic_state *)opaque;

    offset -= s->base;

    switch (offset) {

    case 0x00: /* Control */

        s->cpu_enabled = (value & 1);

        DPRINTF("CPU %sabled\n", s->cpu_enabled ? "En" : "Dis");

        break;

    case 0x04: /* Priority mask */

        s->priority_mask = (value & 0x3ff);

        break;

    case 0x08: /* Binary Point */

        /* ??? Not implemented.  */

        break;

    case 0x10: /* End Of Interrupt */

        return gic_complete_irq(s, value & 0x3ff);

    default:

        cpu_abort (cpu_single_env, "gic_cpu_writeb: Bad offset %x\n", offset);

        return;

    }

    gic_update(s);

}

static CPUReadMemoryFunc *gic_cpu_readfn[] = {

   gic_cpu_read,

   gic_cpu_read,

   gic_cpu_read

};

static CPUWriteMemoryFunc *gic_cpu_writefn[] = {

   gic_cpu_write,

   gic_cpu_write,

   gic_cpu_write

};

static void gic_reset(gic_state *s)

{

    int i;

    memset(s->irq_state, 0, GIC_NIRQ * sizeof(gic_irq_state));

    s->priority_mask = 0xf0;

    s->current_pending = 1023;

    s->running_irq = 1023;

    s->running_priority = 0x100;

    for (i = 0; i < 15; i++) {

        GIC_SET_ENABLED(i);

        GIC_SET_TRIGGER(i);

    }

    s->enabled = 0;

    s->cpu_enabled = 0;

}

void *arm_gic_init(uint32_t base, void *parent, int parent_irq)

{

    gic_state *s;

    int iomemtype;

    s = (gic_state *)qemu_mallocz(sizeof(gic_state));

    if (!s)

        return NULL;

    s->handler = gic_set_irq;

    s->parent = parent;

    s->parent_irq = parent_irq;

    if (base != 0xffffffff) {

        iomemtype = cpu_register_io_memory(0, gic_cpu_readfn,

                                           gic_cpu_writefn, s);

        cpu_register_physical_memory(base, 0x00000fff, iomemtype);

        iomemtype = cpu_register_io_memory(0, gic_dist_readfn,

                                           gic_dist_writefn, s);

        cpu_register_physical_memory(base + 0x1000, 0x00000fff, iomemtype);

        s->base = base;

    } else {

        s->base = 0;

    }

    gic_reset(s);

    return s;

}