/*

 * ARM Nested Vectored Interrupt Controller

 *

 * Copyright (c) 2006-2007 CodeSourcery.

 * Written by Paul Brook

 *

 * This code is licenced under the GPL.

 *

 * The ARMv7M System controller is fairly tightly tied in with the

 * NVIC.  Much of that is also implemented here.

 */

#include "hw.h"

#include "qemu-timer.h"

#include "arm-misc.h"

/* 32 internal lines (16 used for system exceptions) plus 64 external

   interrupt lines.  */

#define GIC_NIRQ 96

#define NCPU 1

#define NVIC 1

/* Only a single "CPU" interface is present.  */

static inline int

gic_get_current_cpu(void)

{

    return 0;

}

static uint32_t nvic_readl(void *opaque, uint32_t offset);

static void nvic_writel(void *opaque, uint32_t offset, uint32_t value);

#include "arm_gic.c"

typedef struct {

    struct {

        uint32_t control;

        uint32_t reload;

        int64_t tick;

        QEMUTimer *timer;

    } systick;

    gic_state *gic;

} nvic_state;

/* qemu timers run at 1GHz.   We want something closer to 1MHz.  */

#define SYSTICK_SCALE 1000ULL

#define SYSTICK_ENABLE    (1 << 0)

#define SYSTICK_TICKINT   (1 << 1)

#define SYSTICK_CLKSOURCE (1 << 2)

#define SYSTICK_COUNTFLAG (1 << 16)

int system_clock_scale;

/* Conversion factor from qemu timer to SysTick frequencies.  */

static inline int64_t systick_scale(nvic_state *s)

{

    if (s->systick.control & SYSTICK_CLKSOURCE)

        return system_clock_scale;

    else

        return 1000;

}

static void systick_reload(nvic_state *s, int reset)

{

    if (reset)

        s->systick.tick = qemu_get_clock(vm_clock);

    s->systick.tick += (s->systick.reload + 1) * systick_scale(s);

    qemu_mod_timer(s->systick.timer, s->systick.tick);

}

static void systick_timer_tick(void * opaque)

{

    nvic_state *s = (nvic_state *)opaque;

    s->systick.control |= SYSTICK_COUNTFLAG;

    if (s->systick.control & SYSTICK_TICKINT) {

        /* Trigger the interrupt.  */

        armv7m_nvic_set_pending(s, ARMV7M_EXCP_SYSTICK);

    }

    if (s->systick.reload == 0) {

        s->systick.control &= ~SYSTICK_ENABLE;

    } else {

        systick_reload(s, 0);

    }

}

/* The external routines use the hardware vector numbering, ie. the first

   IRQ is #16.  The internal GIC routines use #32 as the first IRQ.  */

void armv7m_nvic_set_pending(void *opaque, int irq)

{

    nvic_state *s = (nvic_state *)opaque;

    if (irq >= 16)

        irq += 16;

    gic_set_pending_private(s->gic, 0, irq);

}

/* Make pending IRQ active.  */

int armv7m_nvic_acknowledge_irq(void *opaque)

{

    nvic_state *s = (nvic_state *)opaque;

    uint32_t irq;

    irq = gic_acknowledge_irq(s->gic, 0);

    if (irq == 1023)

        cpu_abort(cpu_single_env, "Interrupt but no vector\n");

    if (irq >= 32)

        irq -= 16;

    return irq;

}

void armv7m_nvic_complete_irq(void *opaque, int irq)

{

    nvic_state *s = (nvic_state *)opaque;

    if (irq >= 16)

        irq += 16;

    gic_complete_irq(s->gic, 0, irq);

}

static uint32_t nvic_readl(void *opaque, uint32_t offset)

{

    nvic_state *s = (nvic_state *)opaque;

    uint32_t val;

    int irq;

    switch (offset) {

    case 4: /* Interrupt Control Type.  */

        return (GIC_NIRQ / 32) - 1;

    case 0x10: /* SysTick Control and Status.  */

        val = s->systick.control;

        s->systick.control &= ~SYSTICK_COUNTFLAG;

        return val;

    case 0x14: /* SysTick Reload Value.  */

        return s->systick.reload;

    case 0x18: /* SysTick Current Value.  */

        {

            int64_t t;

            if ((s->systick.control & SYSTICK_ENABLE) == 0)

                return 0;

            t = qemu_get_clock(vm_clock);

            if (t >= s->systick.tick)

                return 0;

            val = ((s->systick.tick - (t + 1)) / systick_scale(s)) + 1;

            /* The interrupt in triggered when the timer reaches zero.

               However the counter is not reloaded until the next clock

               tick.  This is a hack to return zero during the first tick.  */

            if (val > s->systick.reload)

                val = 0;

            return val;

        }

    case 0x1c: /* SysTick Calibration Value.  */

        return 10000;

    case 0xd00: /* CPUID Base.  */

        return cpu_single_env->cp15.c0_cpuid;

    case 0xd04: /* Interrypt Control State.  */

        /* VECTACTIVE */

        val = s->gic->running_irq[0];

        if (val == 1023) {

            val = 0;

        } else if (val >= 32) {

            val -= 16;

        }

        /* RETTOBASE */

        if (s->gic->running_irq[0] == 1023

                || s->gic->last_active[s->gic->running_irq[0]][0] == 1023) {

            val |= (1 << 11);

        }

        /* VECTPENDING */

        if (s->gic->current_pending[0] != 1023)

            val |= (s->gic->current_pending[0] << 12);

        /* ISRPENDING */

        for (irq = 32; irq < GIC_NIRQ; irq++) {

            if (s->gic->irq_state[irq].pending) {

                val |= (1 << 22);

                break;

            }

        }

        /* PENDSTSET */

        if (s->gic->irq_state[ARMV7M_EXCP_SYSTICK].pending)

            val |= (1 << 26);

        /* PENDSVSET */

        if (s->gic->irq_state[ARMV7M_EXCP_PENDSV].pending)

            val |= (1 << 28);

        /* NMIPENDSET */

        if (s->gic->irq_state[ARMV7M_EXCP_NMI].pending)

            val |= (1 << 31);

        return val;

    case 0xd08: /* Vector Table Offset.  */

        return cpu_single_env->v7m.vecbase;

    case 0xd0c: /* Application Interrupt/Reset Control.  */

        return 0xfa05000;

    case 0xd10: /* System Control.  */

        /* TODO: Implement SLEEPONEXIT.  */

        return 0;

    case 0xd14: /* Configuration Control.  */

        /* TODO: Implement Configuration Control bits.  */

        return 0;

    case 0xd18: case 0xd1c: case 0xd20: /* System Handler Priority.  */

        irq = offset - 0xd14;

        val = 0;

        val = s->gic->priority1[irq++][0];

        val = s->gic->priority1[irq++][0] << 8;

        val = s->gic->priority1[irq++][0] << 16;

        val = s->gic->priority1[irq][0] << 24;

        return val;

    case 0xd24: /* System Handler Status.  */

        val = 0;

        if (s->gic->irq_state[ARMV7M_EXCP_MEM].active) val |= (1 << 0);

        if (s->gic->irq_state[ARMV7M_EXCP_BUS].active) val |= (1 << 1);

        if (s->gic->irq_state[ARMV7M_EXCP_USAGE].active) val |= (1 << 3);

        if (s->gic->irq_state[ARMV7M_EXCP_SVC].active) val |= (1 << 7);

        if (s->gic->irq_state[ARMV7M_EXCP_DEBUG].active) val |= (1 << 8);

        if (s->gic->irq_state[ARMV7M_EXCP_PENDSV].active) val |= (1 << 10);

        if (s->gic->irq_state[ARMV7M_EXCP_SYSTICK].active) val |= (1 << 11);

        if (s->gic->irq_state[ARMV7M_EXCP_USAGE].pending) val |= (1 << 12);

        if (s->gic->irq_state[ARMV7M_EXCP_MEM].pending) val |= (1 << 13);

        if (s->gic->irq_state[ARMV7M_EXCP_BUS].pending) val |= (1 << 14);

        if (s->gic->irq_state[ARMV7M_EXCP_SVC].pending) val |= (1 << 15);

        if (s->gic->irq_state[ARMV7M_EXCP_MEM].enabled) val |= (1 << 16);

        if (s->gic->irq_state[ARMV7M_EXCP_BUS].enabled) val |= (1 << 17);

        if (s->gic->irq_state[ARMV7M_EXCP_USAGE].enabled) val |= (1 << 18);

        return val;

    case 0xd28: /* Configurable Fault Status.  */

        /* TODO: Implement Fault Status.  */

        cpu_abort(cpu_single_env,

                  "Not implemented: Configurable Fault Status.");

        return 0;

    case 0xd2c: /* Hard Fault Status.  */

    case 0xd30: /* Debug Fault Status.  */

    case 0xd34: /* Mem Manage Address.  */

    case 0xd38: /* Bus Fault Address.  */

    case 0xd3c: /* Aux Fault Status.  */

        /* TODO: Implement fault status registers.  */

        goto bad_reg;

    case 0xd40: /* PFR0.  */

        return 0x00000030;

    case 0xd44: /* PRF1.  */

        return 0x00000200;

    case 0xd48: /* DFR0.  */

        return 0x00100000;

    case 0xd4c: /* AFR0.  */

        return 0x00000000;

    case 0xd50: /* MMFR0.  */

        return 0x00000030;

    case 0xd54: /* MMFR1.  */

        return 0x00000000;

    case 0xd58: /* MMFR2.  */

        return 0x00000000;

    case 0xd5c: /* MMFR3.  */

        return 0x00000000;

    case 0xd60: /* ISAR0.  */

        return 0x01141110;

    case 0xd64: /* ISAR1.  */

        return 0x02111000;

    case 0xd68: /* ISAR2.  */

        return 0x21112231;

    case 0xd6c: /* ISAR3.  */

        return 0x01111110;

    case 0xd70: /* ISAR4.  */

        return 0x01310102;

    /* TODO: Implement debug registers.  */

    default:

    bad_reg:

        cpu_abort(cpu_single_env, "NVIC: Bad read offset 0x%x\n", offset);

    }

}

static void nvic_writel(void *opaque, uint32_t offset, uint32_t value)

{

    nvic_state *s = (nvic_state *)opaque;

    uint32_t oldval;

    switch (offset) {

    case 0x10: /* SysTick Control and Status.  */

        oldval = s->systick.control;

        s->systick.control &= 0xfffffff8;

        s->systick.control |= value & 7;

        if ((oldval ^ value) & SYSTICK_ENABLE) {

            int64_t now = qemu_get_clock(vm_clock);

            if (value & SYSTICK_ENABLE) {

                if (s->systick.tick) {

                    s->systick.tick += now;

                    qemu_mod_timer(s->systick.timer, s->systick.tick);

                } else {

                    systick_reload(s, 1);

                }

            } else {

                qemu_del_timer(s->systick.timer);

                s->systick.tick -= now;

                if (s->systick.tick < 0)

                  s->systick.tick = 0;

            }

        } else if ((oldval ^ value) & SYSTICK_CLKSOURCE) {

            /* This is a hack. Force the timer to be reloaded

               when the reference clock is changed.  */

            systick_reload(s, 1);

        }

        break;

    case 0x14: /* SysTick Reload Value.  */

        s->systick.reload = value;

        break;

    case 0x18: /* SysTick Current Value.  Writes reload the timer.  */

        systick_reload(s, 1);

        s->systick.control &= ~SYSTICK_COUNTFLAG;

        break;

    case 0xd04: /* Interrupt Control State.  */

        if (value & (1 << 31)) {

            armv7m_nvic_set_pending(s, ARMV7M_EXCP_NMI);

        }

        if (value & (1 << 28)) {

            armv7m_nvic_set_pending(s, ARMV7M_EXCP_PENDSV);

        } else if (value & (1 << 27)) {

            s->gic->irq_state[ARMV7M_EXCP_PENDSV].pending = 0;

            gic_update(s->gic);

        }

        if (value & (1 << 26)) {

            armv7m_nvic_set_pending(s, ARMV7M_EXCP_SYSTICK);

        } else if (value & (1 << 25)) {

            s->gic->irq_state[ARMV7M_EXCP_SYSTICK].pending = 0;

            gic_update(s->gic);

        }

        break;

    case 0xd08: /* Vector Table Offset.  */

        cpu_single_env->v7m.vecbase = value & 0xffffff80;

        break;

    case 0xd0c: /* Application Interrupt/Reset Control.  */

        if ((value >> 16) == 0x05fa) {

            if (value & 2) {

                cpu_abort(cpu_single_env, "VECTCLRACTIVE not implemented");

            }

            if (value & 5) {

                cpu_abort(cpu_single_env, "System reset");

            }

        }

        break;

    case 0xd10: /* System Control.  */

    case 0xd14: /* Configuration Control.  */

        /* TODO: Implement control registers.  */

        goto bad_reg;

    case 0xd18: case 0xd1c: case 0xd20: /* System Handler Priority.  */

        {

            int irq;

            irq = offset - 0xd14;

            s->gic->priority1[irq++][0] = value & 0xff;

            s->gic->priority1[irq++][0] = (value >> 8) & 0xff;

            s->gic->priority1[irq++][0] = (value >> 16) & 0xff;

            s->gic->priority1[irq][0] = (value >> 24) & 0xff;

            gic_update(s->gic);

        }

        break;

    case 0xd24: /* System Handler Control.  */

        /* TODO: Real hardware allows you to set/clear the active bits

           under some circumstances.  We don't implement this.  */

        s->gic->irq_state[ARMV7M_EXCP_MEM].enabled = (value & (1 << 16)) != 0;

        s->gic->irq_state[ARMV7M_EXCP_BUS].enabled = (value & (1 << 17)) != 0;

        s->gic->irq_state[ARMV7M_EXCP_USAGE].enabled = (value & (1 << 18)) != 0;

        break;

    case 0xd28: /* Configurable Fault Status.  */

    case 0xd2c: /* Hard Fault Status.  */

    case 0xd30: /* Debug Fault Status.  */

    case 0xd34: /* Mem Manage Address.  */

    case 0xd38: /* Bus Fault Address.  */

    case 0xd3c: /* Aux Fault Status.  */

        goto bad_reg;

    default:

    bad_reg:

        cpu_abort(cpu_single_env, "NVIC: Bad write offset 0x%x\n", offset);

    }

}

static void nvic_save(QEMUFile *f, void *opaque)

{

    nvic_state *s = (nvic_state *)opaque;

    qemu_put_be32(f, s->systick.control);

    qemu_put_be32(f, s->systick.reload);

    qemu_put_be64(f, s->systick.tick);

    qemu_put_timer(f, s->systick.timer);

}

static int nvic_load(QEMUFile *f, void *opaque, int version_id)

{

    nvic_state *s = (nvic_state *)opaque;

    if (version_id != 1)

        return -EINVAL;

    s->systick.control = qemu_get_be32(f);

    s->systick.reload = qemu_get_be32(f);

    s->systick.tick = qemu_get_be64(f);

    qemu_get_timer(f, s->systick.timer);

    return 0;

}

qemu_irq *armv7m_nvic_init(CPUState *env)

{

    nvic_state *s;

    qemu_irq *parent;

    parent = arm_pic_init_cpu(env);

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

    s->gic = gic_init(0xe000e000, &parent[ARM_PIC_CPU_IRQ]);

    s->gic->nvic = s;

    s->systick.timer = qemu_new_timer(vm_clock, systick_timer_tick, s);

    if (env->v7m.nvic)

        cpu_abort(env, "CPU can only have one NVIC\n");

    env->v7m.nvic = s;

    register_savevm("armv7m_nvic", -1, 1, nvic_save, nvic_load, s);

    return s->gic->in;

}