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/*

 * ARM Generic/Distributed Interrupt Controller

 *

 * Copyright (c) 2006-2007 CodeSourcery.

 * Written by Paul Brook

 *

 * This code is licensed 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.

 * It is compiled in two ways:

 *  (1) as a standalone file to produce a sysbus device which is a GIC

 *  that can be used on the realview board and as one of the builtin

 *  private peripherals for the ARM MP CPUs (11MPCore, A9, etc)

 *  (2) by being directly #included into armv7m_nvic.c to produce the

 *  armv7m_nvic device.

 */

#include "sysbus.h"

#include "arm_gic_internal.h"

//#define DEBUG_GIC

#ifdef DEBUG_GIC

#define DPRINTF(fmt, ...) \

do { fprintf(stderr, "arm_gic: " fmt , ## __VA_ARGS__); } while (0)

#else

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

#endif

static const uint8_t gic_id[] = {

    0x90, 0x13, 0x04, 0x00, 0x0d, 0xf0, 0x05, 0xb1

};

#define NUM_CPU(s) ((s)->num_cpu)

static inline int gic_get_current_cpu(gic_state *s)

{

    if (s->num_cpu > 1) {

        return cpu_single_env->cpu_index;

    }

    return 0;

}

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

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

void gic_update(gic_state *s)

{

    int best_irq;

    int best_prio;

    int irq;

    int level;

    int cpu;

    int cm;

    for (cpu = 0; cpu < NUM_CPU(s); 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 < s->num_irq; irq++) {

            if (GIC_TEST_ENABLED(irq, cm) && 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);

    }

}

void 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)

{

    /* Meaning of the 'irq' parameter:

     *  [0..N-1] : external interrupts

     *  [N..N+31] : PPI (internal) interrupts for CPU 0

     *  [N+32..N+63] : PPI (internal interrupts for CPU 1

     *  ...

     */

    gic_state *s = (gic_state *)opaque;

    int cm, target;

    if (irq < (s->num_irq - GIC_INTERNAL)) {

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

        cm = ALL_CPU_MASK;

        irq += GIC_INTERNAL;

        target = GIC_TARGET(irq);

    } else {

        int cpu;

        irq -= (s->num_irq - GIC_INTERNAL);

        cpu = irq / GIC_INTERNAL;

        irq %= GIC_INTERNAL;

        cm = 1 << cpu;

        target = cm;

    }

    if (level == GIC_TEST_LEVEL(irq, cm)) {

        return;

    }

    if (level) {

        GIC_SET_LEVEL(irq, cm);

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

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

            GIC_SET_PENDING(irq, target);

        }

    } else {

        GIC_CLEAR_LEVEL(irq, cm);

    }

    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);

}

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;

}

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

{

    int update = 0;

    int cm = 1 << cpu;

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

    if (irq >= s->num_irq) {

        /* This handles two cases:

         * 1. If software writes the ID of a spurious interrupt [ie 1023]

         * to the GICC_EOIR, the GIC ignores that write.

         * 2. If software writes the number of a non-existent interrupt

         * this must be a subcase of "value written does not match the last

         * valid interrupt value read from the Interrupt Acknowledge

         * register" and so this is UNPREDICTABLE. We choose to ignore it.

         */

        return;

    }

    if (s->running_irq[cpu] == 1023)

        return; /* No active IRQ.  */

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

       raised.  */

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

        && 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(s);

    cm = 1 << cpu;

    if (offset < 0x100) {

        if (offset == 0)

            return s->enabled;

        if (offset == 4)

            return ((s->num_irq / 32) - 1) | ((NUM_CPU(s) - 1) << 5);

        if (offset < 0x08)

            return 0;

        if (offset >= 0x80) {

            /* Interrupt Security , RAZ/WI */

            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;

        irq += GIC_BASE_IRQ;

        if (irq >= s->num_irq)

            goto bad_reg;

        res = 0;

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

            if (GIC_TEST_ENABLED(irq + i, cm)) {

                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 >= s->num_irq)

            goto bad_reg;

        res = 0;

        mask = (irq < GIC_INTERNAL) ?  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 >= s->num_irq)

            goto bad_reg;

        res = 0;

        mask = (irq < GIC_INTERNAL) ?  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 >= s->num_irq)

            goto bad_reg;

        res = GIC_GET_PRIORITY(irq, cpu);

    } else if (offset < 0xc00) {

        /* Interrupt CPU Target.  */

        if (s->num_cpu == 1 && s->revision != REV_11MPCORE) {

            /* For uniprocessor GICs these RAZ/WI */

            res = 0;

        } else {

            irq = (offset - 0x800) + GIC_BASE_IRQ;

            if (irq >= s->num_irq) {

                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 >= s->num_irq)

            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:

    hw_error("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;

    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(s);

    if (offset < 0x100) {

        if (offset == 0) {

            s->enabled = (value & 1);

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

        } else if (offset < 4) {

            /* ignored.  */

        } else if (offset >= 0x80) {

            /* Interrupt Security Registers, RAZ/WI */

        } else {

            goto bad_reg;

        }

    } else if (offset < 0x180) {

        /* Interrupt Set Enable.  */

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

        if (irq >= s->num_irq)

            goto bad_reg;

        if (irq < 16)

          value = 0xff;

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

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

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

                int cm = (irq < GIC_INTERNAL) ? (1 << cpu) : ALL_CPU_MASK;

                if (!GIC_TEST_ENABLED(irq + i, cm)) {

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

                }

                GIC_SET_ENABLED(irq + i, cm);

                /* 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 >= s->num_irq)

            goto bad_reg;

        if (irq < 16)

          value = 0;

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

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

                int cm = (irq < GIC_INTERNAL) ? (1 << cpu) : ALL_CPU_MASK;

                if (GIC_TEST_ENABLED(irq + i, cm)) {

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

                }

                GIC_CLEAR_ENABLED(irq + i, cm);

            }

        }

    } else if (offset < 0x280) {

        /* Interrupt Set Pending.  */

        irq = (offset - 0x200) * 8 + GIC_BASE_IRQ;

        if (irq >= s->num_irq)

            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 >= s->num_irq)

            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 >= s->num_irq)

            goto bad_reg;

        if (irq < GIC_INTERNAL) {

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

        } else {

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

        }

    } else if (offset < 0xc00) {

        /* Interrupt CPU Target. RAZ/WI on uniprocessor GICs, with the

         * annoying exception of the 11MPCore's GIC.

         */

        if (s->num_cpu != 1 || s->revision == REV_11MPCORE) {

            irq = (offset - 0x800) + GIC_BASE_IRQ;

            if (irq >= s->num_irq) {

                goto bad_reg;

            }

            if (irq < 29) {

                value = 0;

            } else if (irq < GIC_INTERNAL) {

                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 >= s->num_irq)

            goto bad_reg;

        if (irq < GIC_INTERNAL)

            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);

            }

        }

    } else {

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

        goto bad_reg;

    }

    gic_update(s);

    return;

bad_reg:

    hw_error("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;

    if (offset == 0xf00) {

        int cpu;

        int irq;

        int mask;

        cpu = gic_get_current_cpu(s);

        irq = value & 0x3ff;

        switch ((value >> 24) & 3) {

        case 0:

            mask = (value >> 16) & ALL_CPU_MASK;

            break;

        case 1:

            mask = ALL_CPU_MASK ^ (1 << cpu);

            break;

        case 2:

            mask = 1 << cpu;

            break;

        default:

            DPRINTF("Bad Soft Int target filter\n");

            mask = ALL_CPU_MASK;

            break;

        }

        GIC_SET_PENDING(irq, mask);

        gic_update(s);

        return;

    }

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

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

}

static const MemoryRegionOps gic_dist_ops = {

    .old_mmio = {

        .read = { gic_dist_readb, gic_dist_readw, gic_dist_readl, },

        .write = { gic_dist_writeb, gic_dist_writew, gic_dist_writel, },

    },

    .endianness = DEVICE_NATIVE_ENDIAN,

};

static uint32_t gic_cpu_read(gic_state *s, int cpu, int offset)

{

    switch (offset) {

    case 0x00: /* Control */

        return s->cpu_enabled[cpu];

    case 0x04: /* Priority mask */

        return s->priority_mask[cpu];

    case 0x08: /* Binary Point */

        /* ??? Not implemented.  */

        return 0;

    case 0x0c: /* Acknowledge */

        return gic_acknowledge_irq(s, cpu);

    case 0x14: /* Running Priority */

        return s->running_priority[cpu];

    case 0x18: /* Highest Pending Interrupt */

        return s->current_pending[cpu];

    default:

        hw_error("gic_cpu_read: Bad offset %x\n", (int)offset);

        return 0;

    }

}

static void gic_cpu_write(gic_state *s, int cpu, int offset, uint32_t value)

{

    switch (offset) {

    case 0x00: /* Control */

        s->cpu_enabled[cpu] = (value & 1);

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

        break;

    case 0x04: /* Priority mask */

        s->priority_mask[cpu] = (value & 0xff);

        break;

    case 0x08: /* Binary Point */

        /* ??? Not implemented.  */

        break;

    case 0x10: /* End Of Interrupt */

        return gic_complete_irq(s, cpu, value & 0x3ff);

    default:

        hw_error("gic_cpu_write: Bad offset %x\n", (int)offset);

        return;

    }

    gic_update(s);

}

/* Wrappers to read/write the GIC CPU interface for the current CPU */

static uint64_t gic_thiscpu_read(void *opaque, target_phys_addr_t addr,

                                 unsigned size)

{

    gic_state *s = (gic_state *)opaque;

    return gic_cpu_read(s, gic_get_current_cpu(s), addr);

}

static void gic_thiscpu_write(void *opaque, target_phys_addr_t addr,

                              uint64_t value, unsigned size)

{

    gic_state *s = (gic_state *)opaque;

    gic_cpu_write(s, gic_get_current_cpu(s), addr, value);

}

/* Wrappers to read/write the GIC CPU interface for a specific CPU.

 * These just decode the opaque pointer into gic_state* + cpu id.

 */

static uint64_t gic_do_cpu_read(void *opaque, target_phys_addr_t addr,

                                unsigned size)

{

    gic_state **backref = (gic_state **)opaque;

    gic_state *s = *backref;

    int id = (backref - s->backref);

    return gic_cpu_read(s, id, addr);

}

static void gic_do_cpu_write(void *opaque, target_phys_addr_t addr,

                             uint64_t value, unsigned size)

{

    gic_state **backref = (gic_state **)opaque;

    gic_state *s = *backref;

    int id = (backref - s->backref);

    gic_cpu_write(s, id, addr, value);

}

static const MemoryRegionOps gic_thiscpu_ops = {

    .read = gic_thiscpu_read,

    .write = gic_thiscpu_write,

    .endianness = DEVICE_NATIVE_ENDIAN,

};

static const MemoryRegionOps gic_cpu_ops = {

    .read = gic_do_cpu_read,

    .write = gic_do_cpu_write,

    .endianness = DEVICE_NATIVE_ENDIAN,

};

void gic_init_irqs_and_distributor(gic_state *s, int num_irq)

{

    int i;

    i = s->num_irq - GIC_INTERNAL;

    /* For the GIC, also expose incoming GPIO lines for PPIs for each CPU.

     * GPIO array layout is thus:

     *  [0..N-1] SPIs

     *  [N..N+31] PPIs for CPU 0

     *  [N+32..N+63] PPIs for CPU 1

     *   ...

     */

    if (s->revision != REV_NVIC) {

        i += (GIC_INTERNAL * s->num_cpu);

    }

    qdev_init_gpio_in(&s->busdev.qdev, gic_set_irq, i);

    for (i = 0; i < NUM_CPU(s); i++) {

        sysbus_init_irq(&s->busdev, &s->parent_irq[i]);

    }

    memory_region_init_io(&s->iomem, &gic_dist_ops, s, "gic_dist", 0x1000);

}

static int arm_gic_init(SysBusDevice *dev)

{

    /* Device instance init function for the GIC sysbus device */

    int i;

    gic_state *s = FROM_SYSBUS(gic_state, dev);

    ARMGICClass *agc = ARM_GIC_GET_CLASS(s);

    agc->parent_init(dev);

    gic_init_irqs_and_distributor(s, s->num_irq);

    /* Memory regions for the CPU interfaces (NVIC doesn't have these):

     * a region for "CPU interface for this core", then a region for

     * "CPU interface for core 0", "for core 1", ...

     * NB that the memory region size of 0x100 applies for the 11MPCore

     * and also cores following the GIC v1 spec (ie A9).

     * GIC v2 defines a larger memory region (0x1000) so this will need

     * to be extended when we implement A15.

     */

    memory_region_init_io(&s->cpuiomem[0], &gic_thiscpu_ops, s,

                          "gic_cpu", 0x100);

    for (i = 0; i < NUM_CPU(s); i++) {

        s->backref[i] = s;

        memory_region_init_io(&s->cpuiomem[i+1], &gic_cpu_ops, &s->backref[i],

                              "gic_cpu", 0x100);

    }

    /* Distributor */

    sysbus_init_mmio(dev, &s->iomem);

    /* cpu interfaces (one for "current cpu" plus one per cpu) */

    for (i = 0; i <= NUM_CPU(s); i++) {

        sysbus_init_mmio(dev, &s->cpuiomem[i]);

    }

    return 0;

}

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

{

    DeviceClass *dc = DEVICE_CLASS(klass);

    SysBusDeviceClass *sbc = SYS_BUS_DEVICE_CLASS(klass);

    ARMGICClass *agc = ARM_GIC_CLASS(klass);

    agc->parent_init = sbc->init;

    sbc->init = arm_gic_init;

    dc->no_user = 1;

}

static TypeInfo arm_gic_info = {

    .name = TYPE_ARM_GIC,

    .parent = TYPE_ARM_GIC_COMMON,

    .instance_size = sizeof(gic_state),

    .class_init = arm_gic_class_init,

};

static void arm_gic_register_types(void)

{

    type_register_static(&arm_gic_info);

}

type_init(arm_gic_register_types)