/*

 * ARM Generic/Distributed Interrupt Controller

 *

 * Copyright (c) 2006-2007 CodeSourcery.

 * Written by Paul Brook

 *

 * This code is licenced under the GPL.

 */

/* This file contains implementation code for the RealView EB interrupt

   controller, MPCore distributed interrupt controller and ARMv7-M

   Nested Vectored Interrupt Controller.  */

//#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

#ifdef NVIC

static const uint8_t gic_id[] =

{ 0x00, 0xb0, 0x1b, 0x00, 0x0d, 0xe0, 0x05, 0xb1 };

/* The NVIC has 16 internal vectors.  However these are not exposed

   through the normal GIC interface.  */

#define GIC_BASE_IRQ    32

#else

static const uint8_t gic_id[] =

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

#define GIC_BASE_IRQ    0

#endif

typedef struct gic_irq_state

{

    /* ??? The documentation seems to imply the enable bits are global, even

       for per-cpu interrupts.  This seems strange.  */

    unsigned enabled:1;

    unsigned pending:NCPU;

    unsigned active:NCPU;

    unsigned level:1;

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

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

} gic_irq_state;

#define ALL_CPU_MASK ((1 << NCPU) - 1)

#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, cm) s->irq_state[irq].pending |= (cm)

#define GIC_CLEAR_PENDING(irq, cm) s->irq_state[irq].pending &= ~(cm)

#define GIC_TEST_PENDING(irq, cm) ((s->irq_state[irq].pending & (cm)) != 0)

#define GIC_SET_ACTIVE(irq, cm) s->irq_state[irq].active |= (cm)

#define GIC_CLEAR_ACTIVE(irq, cm) s->irq_state[irq].active &= ~(cm)

#define GIC_TEST_ACTIVE(irq, cm) ((s->irq_state[irq].active & (cm)) != 0)

#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, cm) s->irq_state[irq].level = (cm)

#define GIC_CLEAR_LEVEL(irq, cm) s->irq_state[irq].level &= ~(cm)

#define GIC_TEST_LEVEL(irq, cm) ((s->irq_state[irq].level & (cm)) != 0)

#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

#define GIC_GET_PRIORITY(irq, cpu) \

  (((irq) < 32) ? s->priority1[irq][cpu] : s->priority2[(irq) - 32])

#ifdef NVIC

#define GIC_TARGET(irq) 1

#else

#define GIC_TARGET(irq) s->irq_target[irq]

#endif

typedef struct gic_state

{

    qemu_irq parent_irq[NCPU];

    int enabled;

    int cpu_enabled[NCPU];

    gic_irq_state irq_state[GIC_NIRQ];

#ifndef NVIC

    int irq_target[GIC_NIRQ];

#endif

    int priority1[32][NCPU];

    int priority2[GIC_NIRQ - 32];

    int last_active[GIC_NIRQ][NCPU];

    int priority_mask[NCPU];

    int running_irq[NCPU];

    int running_priority[NCPU];

    int current_pending[NCPU];

    qemu_irq *in;

#ifdef NVIC

    void *nvic;

#endif

} 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;

    int level;

    int cpu;

    int cm;

    for (cpu = 0; cpu < NCPU; cpu++) {

        cm = 1 << cpu;

        s->current_pending[cpu] = 1023;

        if (!s->enabled || !s->cpu_enabled[cpu]) {

	    qemu_irq_lower(s->parent_irq[cpu]);

            return;

        }

        best_prio = 0x100;

        best_irq = 1023;

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

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

                if (GIC_GET_PRIORITY(irq, cpu) < best_prio) {

                    best_prio = GIC_GET_PRIORITY(irq, cpu);

                    best_irq = irq;

                }

            }

        }

        level = 0;

        if (best_prio <= s->priority_mask[cpu]) {

            s->current_pending[cpu] = best_irq;

            if (best_prio < s->running_priority[cpu]) {

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

                level = 1;

            }

        }

        qemu_set_irq(s->parent_irq[cpu], level);

    }

}

static void __attribute__((unused))

gic_set_pending_private(gic_state *s, int cpu, int irq)

{

    int cm = 1 << cpu;

    if (GIC_TEST_PENDING(irq, cm))

        return;

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

    GIC_SET_PENDING(irq, cm);

    gic_update(s);

}

/* Process a change in an external IRQ input.  */

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, ALL_CPU_MASK))

        return;

    if (level) {

        GIC_SET_LEVEL(irq, ALL_CPU_MASK);

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

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

            GIC_SET_PENDING(irq, GIC_TARGET(irq));

        }

    } else {

        GIC_CLEAR_LEVEL(irq, ALL_CPU_MASK);

    }

    gic_update(s);

}

static void gic_set_running_irq(gic_state *s, int cpu, int irq)

{

    s->running_irq[cpu] = irq;

    if (irq == 1023) {

        s->running_priority[cpu] = 0x100;

    } else {

        s->running_priority[cpu] = GIC_GET_PRIORITY(irq, cpu);

    }

    gic_update(s);

}

static uint32_t gic_acknowledge_irq(gic_state *s, int cpu)

{

    int new_irq;

    int cm = 1 << cpu;

    new_irq = s->current_pending[cpu];

    if (new_irq == 1023

            || GIC_GET_PRIORITY(new_irq, cpu) >= s->running_priority[cpu]) {

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

        return 1023;

    }

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

    /* Clear pending flags for both level and edge triggered interrupts.

       Level triggered IRQs will be reasserted once they become inactive.  */

    GIC_CLEAR_PENDING(new_irq, GIC_TEST_MODEL(new_irq) ? ALL_CPU_MASK : cm);

    gic_set_running_irq(s, cpu, new_irq);

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

    return new_irq;

}

static void gic_complete_irq(gic_state * s, int cpu, int irq)

{

    int update = 0;

    int cm = 1 << cpu;

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

    if (s->running_irq[cpu] == 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, cm) && (GIC_TARGET(irq) & cm) != 0) {

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

            GIC_SET_PENDING(irq, cm);

            update = 1;

        }

    }

    if (irq != s->running_irq[cpu]) {

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

        int tmp = s->running_irq[cpu];

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

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

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

                break;

            }

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

        }

        if (update) {

            gic_update(s);

        }

    } else {

        /* Complete the current running IRQ.  */

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

    }

}

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;

    int cpu;

    int cm;

    int mask;

    cpu = gic_get_current_cpu();

    cm = 1 << cpu;

    if (offset < 0x100) {

#ifndef NVIC

        if (offset == 0)

            return s->enabled;

        if (offset == 4)

            return ((GIC_NIRQ / 32) - 1) | ((NCPU - 1) << 5);

        if (offset < 0x08)

            return 0;

#endif

        goto bad_reg;

    } else if (offset < 0x200) {

        /* Interrupt Set/Clear Enable.  */

        if (offset < 0x180)

            irq = (offset - 0x100) * 8;

        else

            irq = (offset - 0x180) * 8;

        irq += GIC_BASE_IRQ;

        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;

        irq += GIC_BASE_IRQ;

        if (irq >= GIC_NIRQ)

            goto bad_reg;

        res = 0;

        mask = (irq < 32) ?  cm : ALL_CPU_MASK;

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

            if (GIC_TEST_PENDING(irq + i, mask)) {

                res |= (1 << i);

            }

        }

    } else if (offset < 0x400) {

        /* Interrupt Active.  */

        irq = (offset - 0x300) * 8 + GIC_BASE_IRQ;

        if (irq >= GIC_NIRQ)

            goto bad_reg;

        res = 0;

        mask = (irq < 32) ?  cm : ALL_CPU_MASK;

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

            if (GIC_TEST_ACTIVE(irq + i, mask)) {

                res |= (1 << i);

            }

        }

    } else if (offset < 0x800) {

        /* Interrupt Priority.  */

        irq = (offset - 0x400) + GIC_BASE_IRQ;

        if (irq >= GIC_NIRQ)

            goto bad_reg;

        res = GIC_GET_PRIORITY(irq, cpu);

#ifndef NVIC

    } else if (offset < 0xc00) {

        /* Interrupt CPU Target.  */

        irq = (offset - 0x800) + GIC_BASE_IRQ;

        if (irq >= GIC_NIRQ)

            goto bad_reg;

        if (irq >= 29 && irq <= 31) {

            res = cm;

        } else {

            res = GIC_TARGET(irq);

        }

    } else if (offset < 0xf00) {

        /* Interrupt Configuration.  */

        irq = (offset - 0xc00) * 2 + GIC_BASE_IRQ;

        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));

        }

#endif

    } 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", (int)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;

#ifdef NVIC

    gic_state *s = (gic_state *)opaque;

    uint32_t addr;

    addr = offset;

    if (addr < 0x100 || addr > 0xd00)

        return nvic_readl(s->nvic, addr);

#endif

    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;

    int cpu;

    cpu = gic_get_current_cpu();

    if (offset < 0x100) {

#ifdef NVIC

        goto bad_reg;

#else

        if (offset == 0) {

            s->enabled = (value & 1);

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

        } else if (offset < 4) {

            /* ignored.  */

        } else {

            goto bad_reg;

        }

#endif

    } else if (offset < 0x180) {

        /* Interrupt Set Enable.  */

        irq = (offset - 0x100) * 8 + GIC_BASE_IRQ;

        if (irq >= GIC_NIRQ)

            goto bad_reg;

        if (irq < 16)

          value = 0xff;

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

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

                int mask = (irq < 32) ? (1 << cpu) : GIC_TARGET(irq);

                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, mask)

                        && !GIC_TEST_TRIGGER(irq + i)) {

                    DPRINTF("Set %d pending mask %x\n", irq + i, mask);

                    GIC_SET_PENDING(irq + i, mask);

                }

            }

        }

    } else if (offset < 0x200) {

        /* Interrupt Clear Enable.  */

        irq = (offset - 0x180) * 8 + GIC_BASE_IRQ;

        if (irq >= GIC_NIRQ)

            goto bad_reg;

        if (irq < 16)

          value = 0;

        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 + GIC_BASE_IRQ;

        if (irq >= GIC_NIRQ)

            goto bad_reg;

        if (irq < 16)

          irq = 0;

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

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

                GIC_SET_PENDING(irq + i, GIC_TARGET(irq));

            }

        }

    } else if (offset < 0x300) {

        /* Interrupt Clear Pending.  */

        irq = (offset - 0x280) * 8 + GIC_BASE_IRQ;

        if (irq >= GIC_NIRQ)

            goto bad_reg;

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

            /* ??? This currently clears the pending bit for all CPUs, even

               for per-CPU interrupts.  It's unclear whether this is the

               corect behavior.  */

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

                GIC_CLEAR_PENDING(irq + i, ALL_CPU_MASK);

            }

        }

    } else if (offset < 0x400) {

        /* Interrupt Active.  */

        goto bad_reg;

    } else if (offset < 0x800) {

        /* Interrupt Priority.  */

        irq = (offset - 0x400) + GIC_BASE_IRQ;

        if (irq >= GIC_NIRQ)

            goto bad_reg;

        if (irq < 32) {

            s->priority1[irq][cpu] = value;

        } else {

            s->priority2[irq - 32] = value;

        }

#ifndef NVIC

    } else if (offset < 0xc00) {

        /* Interrupt CPU Target.  */

        irq = (offset - 0x800) + GIC_BASE_IRQ;

        if (irq >= GIC_NIRQ)

            goto bad_reg;

        if (irq < 29)

            value = 0;

        else if (irq < 32)

            value = ALL_CPU_MASK;

        s->irq_target[irq] = value & ALL_CPU_MASK;

    } else if (offset < 0xf00) {

        /* Interrupt Configuration.  */

        irq = (offset - 0xc00) * 4 + GIC_BASE_IRQ;

        if (irq >= GIC_NIRQ)

            goto bad_reg;

        if (irq < 32)

            value |= 0xaa;

        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);

            }

        }

#endif

    } else {

        /* 0xf00 is only handled for 32-bit writes.  */

        goto bad_reg;

    }

    gic_update(s);

    return;

bad_reg:

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

}

static void gic_dist_writew(void *opaque, target_phys_addr_t offset,

                            uint32_t value)

{

    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_state *s = (gic_state *)opaque;

#ifdef NVIC

    uint32_t addr;

    addr = offset;

    if (addr < 0x100 || (addr > 0xd00 && addr != 0xf00)) {

        nvic_writel(s->nvic, addr, value);

        return;

    }