/*
 * Luminary Micro Stellaris peripherals
 *
 * Copyright (c) 2006 CodeSourcery.
 * Written by Paul Brook
 *
 * This code is licensed under the GPL.
 */

#include "hw/sysbus.h"
#include "hw/ssi.h"
#include "hw/arm/arm.h"
#include "hw/devices.h"
#include "qemu/timer.h"
#include "hw/i2c/i2c.h"
#include "net/net.h"
#include "hw/boards.h"
#include "exec/address-spaces.h"

#define GPIO_A 0
#define GPIO_B 1
#define GPIO_C 2
#define GPIO_D 3
#define GPIO_E 4
#define GPIO_F 5
#define GPIO_G 6

#define BP_OLED_I2C  0x01
#define BP_OLED_SSI  0x02
#define BP_GAMEPAD   0x04

typedef const struct {
    const char *name;
    uint32_t did0;
    uint32_t did1;
    uint32_t dc0;
    uint32_t dc1;
    uint32_t dc2;
    uint32_t dc3;
    uint32_t dc4;
    uint32_t peripherals;
} stellaris_board_info;

/* General purpose timer module.  */

#define TYPE_STELLARIS_GPTM "stellaris-gptm"
#define STELLARIS_GPTM(obj) \
    OBJECT_CHECK(gptm_state, (obj), TYPE_STELLARIS_GPTM)

typedef struct gptm_state {
    SysBusDevice parent_obj;

    MemoryRegion iomem;
    uint32_t config;
    uint32_t mode[2];
    uint32_t control;
    uint32_t state;
    uint32_t mask;
    uint32_t load[2];
    uint32_t match[2];
    uint32_t prescale[2];
    uint32_t match_prescale[2];
    uint32_t rtc;
    int64_t tick[2];
    struct gptm_state *opaque[2];
    QEMUTimer *timer[2];
    /* The timers have an alternate output used to trigger the ADC.  */
    qemu_irq trigger;
    qemu_irq irq;
} gptm_state;

static void gptm_update_irq(gptm_state *s)
{
    int level;
    level = (s->state & s->mask) != 0;
    qemu_set_irq(s->irq, level);
}

static void gptm_stop(gptm_state *s, int n)
{
    qemu_del_timer(s->timer[n]);
}

static void gptm_reload(gptm_state *s, int n, int reset)
{
    int64_t tick;
    if (reset)
        tick = qemu_get_clock_ns(vm_clock);
    else
        tick = s->tick[n];

    if (s->config == 0) {
        /* 32-bit CountDown.  */
        uint32_t count;
        count = s->load[0] | (s->load[1] << 16);
        tick += (int64_t)count * system_clock_scale;
    } else if (s->config == 1) {
        /* 32-bit RTC.  1Hz tick.  */
        tick += get_ticks_per_sec();
    } else if (s->mode[n] == 0xa) {
        /* PWM mode.  Not implemented.  */
    } else {
        hw_error("TODO: 16-bit timer mode 0x%x\n", s->mode[n]);
    }
    s->tick[n] = tick;
    qemu_mod_timer(s->timer[n], tick);
}

static void gptm_tick(void *opaque)
{
    gptm_state **p = (gptm_state **)opaque;
    gptm_state *s;
    int n;

    s = *p;
    n = p - s->opaque;
    if (s->config == 0) {
        s->state |= 1;
        if ((s->control & 0x20)) {
            /* Output trigger.  */
	    qemu_irq_pulse(s->trigger);
        }
        if (s->mode[0] & 1) {
            /* One-shot.  */
            s->control &= ~1;
        } else {
            /* Periodic.  */
            gptm_reload(s, 0, 0);
        }
    } else if (s->config == 1) {
        /* RTC.  */
        uint32_t match;
        s->rtc++;
        match = s->match[0] | (s->match[1] << 16);
        if (s->rtc > match)
            s->rtc = 0;
        if (s->rtc == 0) {
            s->state |= 8;
        }
        gptm_reload(s, 0, 0);
    } else if (s->mode[n] == 0xa) {
        /* PWM mode.  Not implemented.  */
    } else {
        hw_error("TODO: 16-bit timer mode 0x%x\n", s->mode[n]);
    }
    gptm_update_irq(s);
}

static uint64_t gptm_read(void *opaque, hwaddr offset,
                          unsigned size)
{
    gptm_state *s = (gptm_state *)opaque;

    switch (offset) {
    case 0x00: /* CFG */
        return s->config;
    case 0x04: /* TAMR */
        return s->mode[0];
    case 0x08: /* TBMR */
        return s->mode[1];
    case 0x0c: /* CTL */
        return s->control;
    case 0x18: /* IMR */
        return s->mask;
    case 0x1c: /* RIS */
        return s->state;
    case 0x20: /* MIS */
        return s->state & s->mask;
    case 0x24: /* CR */
        return 0;
    case 0x28: /* TAILR */
        return s->load[0] | ((s->config < 4) ? (s->load[1] << 16) : 0);
    case 0x2c: /* TBILR */
        return s->load[1];
    case 0x30: /* TAMARCHR */
        return s->match[0] | ((s->config < 4) ? (s->match[1] << 16) : 0);
    case 0x34: /* TBMATCHR */
        return s->match[1];
    case 0x38: /* TAPR */
        return s->prescale[0];
    case 0x3c: /* TBPR */
        return s->prescale[1];
    case 0x40: /* TAPMR */
        return s->match_prescale[0];
    case 0x44: /* TBPMR */
        return s->match_prescale[1];
    case 0x48: /* TAR */
        if (s->control == 1)
            return s->rtc;
    case 0x4c: /* TBR */
        hw_error("TODO: Timer value read\n");
    default:
        hw_error("gptm_read: Bad offset 0x%x\n", (int)offset);
        return 0;
    }
}

static void gptm_write(void *opaque, hwaddr offset,
                       uint64_t value, unsigned size)
{
    gptm_state *s = (gptm_state *)opaque;
    uint32_t oldval;

    /* The timers should be disabled before changing the configuration.
       We take advantage of this and defer everything until the timer
       is enabled.  */
    switch (offset) {
    case 0x00: /* CFG */
        s->config = value;
        break;
    case 0x04: /* TAMR */
        s->mode[0] = value;
        break;
    case 0x08: /* TBMR */
        s->mode[1] = value;
        break;
    case 0x0c: /* CTL */
        oldval = s->control;
        s->control = value;
        /* TODO: Implement pause.  */
        if ((oldval ^ value) & 1) {
            if (value & 1) {
                gptm_reload(s, 0, 1);
            } else {
                gptm_stop(s, 0);
            }
        }
        if (((oldval ^ value) & 0x100) && s->config >= 4) {
            if (value & 0x100) {
                gptm_reload(s, 1, 1);
            } else {
                gptm_stop(s, 1);
            }
        }
        break;
    case 0x18: /* IMR */
        s->mask = value & 0x77;
        gptm_update_irq(s);
        break;
    case 0x24: /* CR */
        s->state &= ~value;
        break;
    case 0x28: /* TAILR */
        s->load[0] = value & 0xffff;
        if (s->config < 4) {
            s->load[1] = value >> 16;
        }
        break;
    case 0x2c: /* TBILR */
        s->load[1] = value & 0xffff;
        break;
    case 0x30: /* TAMARCHR */
        s->match[0] = value & 0xffff;
        if (s->config < 4) {
            s->match[1] = value >> 16;
        }
        break;
    case 0x34: /* TBMATCHR */
        s->match[1] = value >> 16;
        break;
    case 0x38: /* TAPR */
        s->prescale[0] = value;
        break;
    case 0x3c: /* TBPR */
        s->prescale[1] = value;
        break;
    case 0x40: /* TAPMR */
        s->match_prescale[0] = value;
        break;
    case 0x44: /* TBPMR */
        s->match_prescale[0] = value;
        break;
    default:
        hw_error("gptm_write: Bad offset 0x%x\n", (int)offset);
    }
    gptm_update_irq(s);
}

static const MemoryRegionOps gptm_ops = {
    .read = gptm_read,
    .write = gptm_write,
    .endianness = DEVICE_NATIVE_ENDIAN,
};

static const VMStateDescription vmstate_stellaris_gptm = {
    .name = "stellaris_gptm",
    .version_id = 1,
    .minimum_version_id = 1,
    .minimum_version_id_old = 1,
    .fields      = (VMStateField[]) {
        VMSTATE_UINT32(config, gptm_state),
        VMSTATE_UINT32_ARRAY(mode, gptm_state, 2),
        VMSTATE_UINT32(control, gptm_state),
        VMSTATE_UINT32(state, gptm_state),
        VMSTATE_UINT32(mask, gptm_state),
        VMSTATE_UNUSED(8),
        VMSTATE_UINT32_ARRAY(load, gptm_state, 2),
        VMSTATE_UINT32_ARRAY(match, gptm_state, 2),
        VMSTATE_UINT32_ARRAY(prescale, gptm_state, 2),
        VMSTATE_UINT32_ARRAY(match_prescale, gptm_state, 2),
        VMSTATE_UINT32(rtc, gptm_state),
        VMSTATE_INT64_ARRAY(tick, gptm_state, 2),
        VMSTATE_TIMER_ARRAY(timer, gptm_state, 2),
        VMSTATE_END_OF_LIST()
    }
};

static int stellaris_gptm_init(SysBusDevice *sbd)
{
    DeviceState *dev = DEVICE(sbd);
    gptm_state *s = STELLARIS_GPTM(dev);

    sysbus_init_irq(sbd, &s->irq);
    qdev_init_gpio_out(dev, &s->trigger, 1);

    memory_region_init_io(&s->iomem, OBJECT(s), &gptm_ops, s,
                          "gptm", 0x1000);
    sysbus_init_mmio(sbd, &s->iomem);

    s->opaque[0] = s->opaque[1] = s;
    s->timer[0] = qemu_new_timer_ns(vm_clock, gptm_tick, &s->opaque[0]);
    s->timer[1] = qemu_new_timer_ns(vm_clock, gptm_tick, &s->opaque[1]);
    vmstate_register(dev, -1, &vmstate_stellaris_gptm, s);
    return 0;
}


/* System controller.  */

typedef struct {
    MemoryRegion iomem;
    uint32_t pborctl;
    uint32_t ldopctl;
    uint32_t int_status;
    uint32_t int_mask;
    uint32_t resc;
    uint32_t rcc;
    uint32_t rcc2;
    uint32_t rcgc[3];
    uint32_t scgc[3];
    uint32_t dcgc[3];
    uint32_t clkvclr;
    uint32_t ldoarst;
    uint32_t user0;
    uint32_t user1;
    qemu_irq irq;
    stellaris_board_info *board;
} ssys_state;

static void ssys_update(ssys_state *s)
{
  qemu_set_irq(s->irq, (s->int_status & s->int_mask) != 0);
}

static uint32_t pllcfg_sandstorm[16] = {
    0x31c0, /* 1 Mhz */
    0x1ae0, /* 1.8432 Mhz */
    0x18c0, /* 2 Mhz */
    0xd573, /* 2.4576 Mhz */
    0x37a6, /* 3.57954 Mhz */
    0x1ae2, /* 3.6864 Mhz */
    0x0c40, /* 4 Mhz */
    0x98bc, /* 4.906 Mhz */
    0x935b, /* 4.9152 Mhz */
    0x09c0, /* 5 Mhz */
    0x4dee, /* 5.12 Mhz */
    0x0c41, /* 6 Mhz */
    0x75db, /* 6.144 Mhz */
    0x1ae6, /* 7.3728 Mhz */
    0x0600, /* 8 Mhz */
    0x585b /* 8.192 Mhz */
};

static uint32_t pllcfg_fury[16] = {
    0x3200, /* 1 Mhz */
    0x1b20, /* 1.8432 Mhz */
    0x1900, /* 2 Mhz */
    0xf42b, /* 2.4576 Mhz */
    0x37e3, /* 3.57954 Mhz */
    0x1b21, /* 3.6864 Mhz */
    0x0c80, /* 4 Mhz */
    0x98ee, /* 4.906 Mhz */
    0xd5b4, /* 4.9152 Mhz */
    0x0a00, /* 5 Mhz */
    0x4e27, /* 5.12 Mhz */
    0x1902, /* 6 Mhz */
    0xec1c, /* 6.144 Mhz */
    0x1b23, /* 7.3728 Mhz */
    0x0640, /* 8 Mhz */
    0xb11c /* 8.192 Mhz */
};

#define DID0_VER_MASK        0x70000000
#define DID0_VER_0           0x00000000
#define DID0_VER_1           0x10000000

#define DID0_CLASS_MASK      0x00FF0000
#define DID0_CLASS_SANDSTORM 0x00000000
#define DID0_CLASS_FURY      0x00010000

static int ssys_board_class(const ssys_state *s)
{
    uint32_t did0 = s->board->did0;
    switch (did0 & DID0_VER_MASK) {
    case DID0_VER_0:
        return DID0_CLASS_SANDSTORM;
    case DID0_VER_1:
        switch (did0 & DID0_CLASS_MASK) {
        case DID0_CLASS_SANDSTORM:
        case DID0_CLASS_FURY:
            return did0 & DID0_CLASS_MASK;
        }
        /* for unknown classes, fall through */
    default:
        hw_error("ssys_board_class: Unknown class 0x%08x\n", did0);
    }
}

static uint64_t ssys_read(void *opaque, hwaddr offset,
                          unsigned size)
{
    ssys_state *s = (ssys_state *)opaque;

    switch (offset) {
    case 0x000: /* DID0 */
        return s->board->did0;
    case 0x004: /* DID1 */
        return s->board->did1;
    case 0x008: /* DC0 */
        return s->board->dc0;
    case 0x010: /* DC1 */
        return s->board->dc1;
    case 0x014: /* DC2 */
        return s->board->dc2;
    case 0x018: /* DC3 */
        return s->board->dc3;
    case 0x01c: /* DC4 */
        return s->board->dc4;
    case 0x030: /* PBORCTL */
        return s->pborctl;
    case 0x034: /* LDOPCTL */
        return s->ldopctl;
    case 0x040: /* SRCR0 */
        return 0;
    case 0x044: /* SRCR1 */
        return 0;
    case 0x048: /* SRCR2 */
        return 0;
    case 0x050: /* RIS */
        return s->int_status;
    case 0x054: /* IMC */
        return s->int_mask;
    case 0x058: /* MISC */
        return s->int_status & s->int_mask;
    case 0x05c: /* RESC */
        return s->resc;
    case 0x060: /* RCC */
        return s->rcc;
    case 0x064: /* PLLCFG */
        {
            int xtal;
            xtal = (s->rcc >> 6) & 0xf;
            switch (ssys_board_class(s)) {
            case DID0_CLASS_FURY:
                return pllcfg_fury[xtal];
            case DID0_CLASS_SANDSTORM:
                return pllcfg_sandstorm[xtal];
            default:
                hw_error("ssys_read: Unhandled class for PLLCFG read.\n");
                return 0;
            }
        }
    case 0x070: /* RCC2 */
        return s->rcc2;
    case 0x100: /* RCGC0 */
        return s->rcgc[0];
    case 0x104: /* RCGC1 */
        return s->rcgc[1];
    case 0x108: /* RCGC2 */
        return s->rcgc[2];
    case 0x110: /* SCGC0 */
        return s->scgc[0];
    case 0x114: /* SCGC1 */
        return s->scgc[1];
    case 0x118: /* SCGC2 */
        return s->scgc[2];
    case 0x120: /* DCGC0 */
        return s->dcgc[0];
    case 0x124: /* DCGC1 */
        return s->dcgc[1];
    case 0x128: /* DCGC2 */
        return s->dcgc[2];
    case 0x150: /* CLKVCLR */
        return s->clkvclr;
    case 0x160: /* LDOARST */
        return s->ldoarst;
    case 0x1e0: /* USER0 */
        return s->user0;
    case 0x1e4: /* USER1 */
        return s->user1;
    default:
        hw_error("ssys_read: Bad offset 0x%x\n", (int)offset);
        return 0;
    }
}

static bool ssys_use_rcc2(ssys_state *s)
{
    return (s->rcc2 >> 31) & 0x1;
}

/*
 * Caculate the sys. clock period in ms.
 */
static void ssys_calculate_system_clock(ssys_state *s)
{
    if (ssys_use_rcc2(s)) {
        system_clock_scale = 5 * (((s->rcc2 >> 23) & 0x3f) + 1);
    } else {
        system_clock_scale = 5 * (((s->rcc >> 23) & 0xf) + 1);
    }
}

static void ssys_write(void *opaque, hwaddr offset,
                       uint64_t value, unsigned size)
{
    ssys_state *s = (ssys_state *)opaque;

    switch (offset) {
    case 0x030: /* PBORCTL */
        s->pborctl = value & 0xffff;
        break;
    case 0x034: /* LDOPCTL */
        s->ldopctl = value & 0x1f;
        break;
    case 0x040: /* SRCR0 */
    case 0x044: /* SRCR1 */
    case 0x048: /* SRCR2 */
        fprintf(stderr, "Peripheral reset not implemented\n");
        break;
    case 0x054: /* IMC */
        s->int_mask = value & 0x7f;
        break;
    case 0x058: /* MISC */
        s->int_status &= ~value;
        break;
    case 0x05c: /* RESC */
        s->resc = value & 0x3f;
        break;
    case 0x060: /* RCC */
        if ((s->rcc & (1 << 13)) != 0 && (value & (1 << 13)) == 0) {
            /* PLL enable.  */
            s->int_status |= (1 << 6);
        }
        s->rcc = value;
        ssys_calculate_system_clock(s);
        break;
    case 0x070: /* RCC2 */
        if (ssys_board_class(s) == DID0_CLASS_SANDSTORM) {
            break;
        }

        if ((s->rcc2 & (1 << 13)) != 0 && (value & (1 << 13)) == 0) {
            /* PLL enable.  */
            s->int_status |= (1 << 6);
        }
        s->rcc2 = value;
        ssys_calculate_system_clock(s);
        break;
    case 0x100: /* RCGC0 */
        s->rcgc[0] = value;
        break;
    case 0x104: /* RCGC1 */
        s->rcgc[1] = value;
        break;
    case 0x108: /* RCGC2 */
        s->rcgc[2] = value;
        break;
    case 0x110: /* SCGC0 */
        s->scgc[0] = value;
        break;
    case 0x114: /* SCGC1 */
        s->scgc[1] = value;
        break;
    case 0x118: /* SCGC2 */
        s->scgc[2] = value;
        break;
    case 0x120: /* DCGC0 */
        s->dcgc[0] = value;
        break;
    case 0x124: /* DCGC1 */
        s->dcgc[1] = value;
        break;
    case 0x128: /* DCGC2 */
        s->dcgc[2] = value;
        break;
    case 0x150: /* CLKVCLR */
        s->clkvclr = value;
        break;
    case 0x160: /* LDOARST */
        s->ldoarst = value;
        break;
    default:
        hw_error("ssys_write: Bad offset 0x%x\n", (int)offset);
    }
    ssys_update(s);
}

static const MemoryRegionOps ssys_ops = {
    .read = ssys_read,
    .write = ssys_write,
    .endianness = DEVICE_NATIVE_ENDIAN,
};

static void ssys_reset(void *opaque)
{
    ssys_state *s = (ssys_state *)opaque;

    s->pborctl = 0x7ffd;
    s->rcc = 0x078e3ac0;

    if (ssys_board_class(s) == DID0_CLASS_SANDSTORM) {
        s->rcc2 = 0;
    } else {
        s->rcc2 = 0x07802810;
    }
    s->rcgc[0] = 1;
    s->scgc[0] = 1;
    s->dcgc[0] = 1;
    ssys_calculate_system_clock(s);
}

static int stellaris_sys_post_load(void *opaque, int version_id)
{
    ssys_state *s = opaque;

    ssys_calculate_system_clock(s);

    return 0;
}

static const VMStateDescription vmstate_stellaris_sys = {
    .name = "stellaris_sys",
    .version_id = 2,
    .minimum_version_id = 1,
    .minimum_version_id_old = 1,
    .post_load = stellaris_sys_post_load,
    .fields      = (VMStateField[]) {
        VMSTATE_UINT32(pborctl, ssys_state),
        VMSTATE_UINT32(ldopctl, ssys_state),
        VMSTATE_UINT32(int_mask, ssys_state),
        VMSTATE_UINT32(int_status, ssys_state),
        VMSTATE_UINT32(resc, ssys_state),
        VMSTATE_UINT32(rcc, ssys_state),
        VMSTATE_UINT32_V(rcc2, ssys_state, 2),
        VMSTATE_UINT32_ARRAY(rcgc, ssys_state, 3),
        VMSTATE_UINT32_ARRAY(scgc, ssys_state, 3),
        VMSTATE_UINT32_ARRAY(dcgc, ssys_state, 3),
        VMSTATE_UINT32(clkvclr, ssys_state),
        VMSTATE_UINT32(ldoarst, ssys_state),
        VMSTATE_END_OF_LIST()
    }
};

static int stellaris_sys_init(uint32_t base, qemu_irq irq,
                              stellaris_board_info * board,
                              uint8_t *macaddr)
{
    ssys_state *s;

    s = (ssys_state *)g_malloc0(sizeof(ssys_state));
    s->irq = irq;
    s->board = board;
    /* Most devices come preprogrammed with a MAC address in the user data. */
    s->user0 = macaddr[0] | (macaddr[1] << 8) | (macaddr[2] << 16);
    s->user1 = macaddr[3] | (macaddr[4] << 8) | (macaddr[5] << 16);

    memory_region_init_io(&s->iomem, NULL, &ssys_ops, s, "ssys", 0x00001000);
    memory_region_add_subregion(get_system_memory(), base, &s->iomem);
    ssys_reset(s);
    vmstate_register(NULL, -1, &vmstate_stellaris_sys, s);
    return 0;
}


/* I2C controller.  */

#define TYPE_STELLARIS_I2C "stellaris-i2c"
#define STELLARIS_I2C(obj) \
    OBJECT_CHECK(stellaris_i2c_state, (obj), TYPE_STELLARIS_I2C)

typedef struct {
    SysBusDevice parent_obj;

    i2c_bus *bus;
    qemu_irq irq;
    MemoryRegion iomem;
    uint32_t msa;
    uint32_t mcs;
    uint32_t mdr;
    uint32_t mtpr;
    uint32_t mimr;
    uint32_t mris;
    uint32_t mcr;
} stellaris_i2c_state;

#define STELLARIS_I2C_MCS_BUSY    0x01
#define STELLARIS_I2C_MCS_ERROR   0x02
#define STELLARIS_I2C_MCS_ADRACK  0x04
#define STELLARIS_I2C_MCS_DATACK  0x08
#define STELLARIS_I2C_MCS_ARBLST  0x10
#define STELLARIS_I2C_MCS_IDLE    0x20
#define STELLARIS_I2C_MCS_BUSBSY  0x40

static uint64_t stellaris_i2c_read(void *opaque, hwaddr offset,
                                   unsigned size)
{
    stellaris_i2c_state *s = (stellaris_i2c_state *)opaque;

    switch (offset) {
    case 0x00: /* MSA */
        return s->msa;
    case 0x04: /* MCS */
        /* We don't emulate timing, so the controller is never busy.  */
        return s->mcs | STELLARIS_I2C_MCS_IDLE;
    case 0x08: /* MDR */
        return s->mdr;
    case 0x0c: /* MTPR */
        return s->mtpr;
    case 0x10: /* MIMR */
        return s->mimr;
    case 0x14: /* MRIS */
        return s->mris;
    case 0x18: /* MMIS */
        return s->mris & s->mimr;
    case 0x20: /* MCR */
        return s->mcr;
    default:
        hw_error("strllaris_i2c_read: Bad offset 0x%x\n", (int)offset);
        return 0;
    }
}

static void stellaris_i2c_update(stellaris_i2c_state *s)
{
    int level;

    level = (s->mris & s->mimr) != 0;
    qemu_set_irq(s->irq, level);
}

static void stellaris_i2c_write(void *opaque, hwaddr offset,
                                uint64_t value, unsigned size)
{
    stellaris_i2c_state *s = (stellaris_i2c_state *)opaque;

    switch (offset) {
    case 0x00: /* MSA */
        s->msa = value & 0xff;
        break;
    case 0x04: /* MCS */
        if ((s->mcr & 0x10) == 0) {
            /* Disabled.  Do nothing.  */
            break;
        }
        /* Grab the bus if this is starting a transfer.  */
        if ((value & 2) && (s->mcs & STELLARIS_I2C_MCS_BUSBSY) == 0) {
            if (i2c_start_transfer(s->bus, s->msa >> 1, s->msa & 1)) {
                s->mcs |= STELLARIS_I2C_MCS_ARBLST;
            } else {
                s->mcs &= ~STELLARIS_I2C_MCS_ARBLST;
                s->mcs |= STELLARIS_I2C_MCS_BUSBSY;
            }
        }
        /* If we don't have the bus then indicate an error.  */
        if (!i2c_bus_busy(s->bus)
                || (s->mcs & STELLARIS_I2C_MCS_BUSBSY) == 0) {
            s->mcs |= STELLARIS_I2C_MCS_ERROR;
            break;
        }
        s->mcs &= ~STELLARIS_I2C_MCS_ERROR;
        if (value & 1) {
            /* Transfer a byte.  */
            /* TODO: Handle errors.  */
            if (s->msa & 1) {
                /* Recv */
                s->mdr = i2c_recv(s->bus) & 0xff;
            } else {
                /* Send */
                i2c_send(s->bus, s->mdr);
            }
            /* Raise an interrupt.  */
            s->mris |= 1;
        }
        if (value & 4) {
            /* Finish transfer.  */
            i2c_end_transfer(s->bus);
            s->mcs &= ~STELLARIS_I2C_MCS_BUSBSY;
        }
        break;
    case 0x08: /* MDR */
        s->mdr = value & 0xff;
        break;
    case 0x0c: /* MTPR */
        s->mtpr = value & 0xff;
        break;
    case 0x10: /* MIMR */
        s->mimr = 1;
        break;
    case 0x1c: /* MICR */
        s->mris &= ~value;
        break;
    case 0x20: /* MCR */
        if (value & 1)
            hw_error(
                      "stellaris_i2c_write: Loopback not implemented\n");
        if (value & 0x20)
            hw_error(
                      "stellaris_i2c_write: Slave mode not implemented\n");
        s->mcr = value & 0x31;
        break;
    default:
        hw_error("stellaris_i2c_write: Bad offset 0x%x\n",
                  (int)offset);
    }
    stellaris_i2c_update(s);
}

static void stellaris_i2c_reset(stellaris_i2c_state *s)
{
    if (s->mcs & STELLARIS_I2C_MCS_BUSBSY)
        i2c_end_transfer(s->bus);

    s->msa = 0;
    s->mcs = 0;
    s->mdr = 0;
    s->mtpr = 1;
    s->mimr = 0;
    s->mris = 0;
    s->mcr = 0;
    stellaris_i2c_update(s);
}

static const MemoryRegionOps stellaris_i2c_ops = {
    .read = stellaris_i2c_read,
    .write = stellaris_i2c_write,
    .endianness = DEVICE_NATIVE_ENDIAN,
};

static const VMStateDescription vmstate_stellaris_i2c = {
    .name = "stellaris_i2c",
    .version_id = 1,
    .minimum_version_id = 1,
    .minimum_version_id_old = 1,
    .fields      = (VMStateField[]) {
        VMSTATE_UINT32(msa, stellaris_i2c_state),
        VMSTATE_UINT32(mcs, stellaris_i2c_state),
        VMSTATE_UINT32(mdr, stellaris_i2c_state),
        VMSTATE_UINT32(mtpr, stellaris_i2c_state),
        VMSTATE_UINT32(mimr, stellaris_i2c_state),
        VMSTATE_UINT32(mris, stellaris_i2c_state),
        VMSTATE_UINT32(mcr, stellaris_i2c_state),
        VMSTATE_END_OF_LIST()
    }
};

static int stellaris_i2c_init(SysBusDevice *sbd)
{
    DeviceState *dev = DEVICE(sbd);
    stellaris_i2c_state *s = STELLARIS_I2C(dev);
    i2c_bus *bus;

    sysbus_init_irq(sbd, &s->irq);
    bus = i2c_init_bus(dev, "i2c");
    s->bus = bus;

    memory_region_init_io(&s->iomem, OBJECT(s), &stellaris_i2c_ops, s,
                          "i2c", 0x1000);
    sysbus_init_mmio(sbd, &s->iomem);
    /* ??? For now we only implement the master interface.  */
    stellaris_i2c_reset(s);
    vmstate_register(dev, -1, &vmstate_stellaris_i2c, s);
    return 0;
}

/* Analogue to Digital Converter.  This is only partially implemented,
   enough for applications that use a combined ADC and timer tick.  */

#define STELLARIS_ADC_EM_CONTROLLER 0
#define STELLARIS_ADC_EM_COMP       1
#define STELLARIS_ADC_EM_EXTERNAL   4
#define STELLARIS_ADC_EM_TIMER      5
#define STELLARIS_ADC_EM_PWM0       6
#define STELLARIS_ADC_EM_PWM1       7
#define STELLARIS_ADC_EM_PWM2       8

#define STELLARIS_ADC_FIFO_EMPTY    0x0100
#define STELLARIS_ADC_FIFO_FULL     0x1000

#define TYPE_STELLARIS_ADC "stellaris-adc"
#define STELLARIS_ADC(obj) \
    OBJECT_CHECK(stellaris_adc_state, (obj), TYPE_STELLARIS_ADC)

typedef struct StellarisADCState {
    SysBusDevice parent_obj;

    MemoryRegion iomem;
    uint32_t actss;
    uint32_t ris;
    uint32_t im;
    uint32_t emux;
    uint32_t ostat;
    uint32_t ustat;
    uint32_t sspri;
    uint32_t sac;
    struct {
        uint32_t state;
        uint32_t data[16];
    } fifo[4];
    uint32_t ssmux[4];
    uint32_t ssctl[4];
    uint32_t noise;
    qemu_irq irq[4];
} stellaris_adc_state;

static uint32_t stellaris_adc_fifo_read(stellaris_adc_state *s, int n)
{
    int tail;

    tail = s->fifo[n].state & 0xf;
    if (s->fifo[n].state & STELLARIS_ADC_FIFO_EMPTY) {
        s->ustat |= 1 << n;
    } else {
        s->fifo[n].state = (s->fifo[n].state & ~0xf) | ((tail + 1) & 0xf);
        s->fifo[n].state &= ~STELLARIS_ADC_FIFO_FULL;
        if (tail + 1 == ((s->fifo[n].state >> 4) & 0xf))
            s->fifo[n].state |= STELLARIS_ADC_FIFO_EMPTY;
    }
    return s->fifo[n].data[tail];
}

static void stellaris_adc_fifo_write(stellaris_adc_state *s, int n,
                                     uint32_t value)
{
    int head;

    /* TODO: Real hardware has limited size FIFOs.  We have a full 16 entry 
       FIFO fir each sequencer.  */
    head = (s->fifo[n].state >> 4) & 0xf;
    if (s->fifo[n].state & STELLARIS_ADC_FIFO_FULL) {
        s->ostat |= 1 << n;
        return;
    }
    s->fifo[n].data[head] = value;
    head = (head + 1) & 0xf;
    s->fifo[n].state &= ~STELLARIS_ADC_FIFO_EMPTY;
    s->fifo[n].state = (s->fifo[n].state & ~0xf0) | (head << 4);
    if ((s->fifo[n].state & 0xf) == head)
        s->fifo[n].state |= STELLARIS_ADC_FIFO_FULL;
}

static void stellaris_adc_update(stellaris_adc_state *s)
{
    int level;
    int n;

    for (n = 0; n < 4; n++) {
        level = (s->ris & s->im & (1 << n)) != 0;
        qemu_set_irq(s->irq[n], level);
    }
}

static void stellaris_adc_trigger(void *opaque, int irq, int level)
{
    stellaris_adc_state *s = (stellaris_adc_state *)opaque;
    int n;

    for (n = 0; n < 4; n++) {
        if ((s->actss & (1 << n)) == 0) {
            continue;
        }

        if (((s->emux >> (n * 4)) & 0xff) != 5) {
            continue;
        }

        /* Some applications use the ADC as a random number source, so introduce
           some variation into the signal.  */
        s->noise = s->noise * 314159 + 1;
        /* ??? actual inputs not implemented.  Return an arbitrary value.  */
        stellaris_adc_fifo_write(s, n, 0x200 + ((s->noise >> 16) & 7));
        s->ris |= (1 << n);
        stellaris_adc_update(s);
    }
}

static void stellaris_adc_reset(stellaris_adc_state *s)
{
    int n;

    for (n = 0; n < 4; n++) {
        s->ssmux[n] = 0;
        s->ssctl[n] = 0;
        s->fifo[n].state = STELLARIS_ADC_FIFO_EMPTY;
    }
}

static uint64_t stellaris_adc_read(void *opaque, hwaddr offset,
                                   unsigned size)
{
    stellaris_adc_state *s = (stellaris_adc_state *)opaque;

    /* TODO: Implement this.  */
    if (offset >= 0x40 && offset < 0xc0) {
        int n;
        n = (offset - 0x40) >> 5;
        switch (offset & 0x1f) {
        case 0x00: /* SSMUX */
            return s->ssmux[n];
        case 0x04: /* SSCTL */
            return s->ssctl[n];
        case 0x08: /* SSFIFO */
            return stellaris_adc_fifo_read(s, n);
        case 0x0c: /* SSFSTAT */
            return s->fifo[n].state;
        default:
            break;
        }
    }
    switch (offset) {
    case 0x00: /* ACTSS */
        return s->actss;
    case 0x04: /* RIS */
        return s->ris;
    case 0x08: /* IM */
        return s->im;
    case 0x0c: /* ISC */
        return s->ris & s->im;
    case 0x10: /* OSTAT */
        return s->ostat;
    case 0x14: /* EMUX */
        return s->emux;
    case 0x18: /* USTAT */
        return s->ustat;
    case 0x20: /* SSPRI */
        return s->sspri;
    case 0x30: /* SAC */
        return s->sac;
    default:
        hw_error("strllaris_adc_read: Bad offset 0x%x\n",
                  (int)offset);
        return 0;
    }
}

static void stellaris_adc_write(void *opaque, hwaddr offset,
                                uint64_t value, unsigned size)
{
    stellaris_adc_state *s = (stellaris_adc_state *)opaque;

    /* TODO: Implement this.  */
    if (offset >= 0x40 && offset < 0xc0) {
        int n;
        n = (offset - 0x40) >> 5;
        switch (offset & 0x1f) {
        case 0x00: /* SSMUX */
            s->ssmux[n] = value & 0x33333333;
            return;
        case 0x04: /* SSCTL */
            if (value != 6) {
                hw_error("ADC: Unimplemented sequence %" PRIx64 "\n",
                          value);
            }
            s->ssctl[n] = value;
            return;
        default:
            break;
        }
    }
    switch (offset) {
    case 0x00: /* ACTSS */
        s->actss = value & 0xf;
        break;
    case 0x08: /* IM */
        s->im = value;
        break;
    case 0x0c: /* ISC */
        s->ris &= ~value;
        break;
    case 0x10: /* OSTAT */
        s->ostat &= ~value;
        break;
    case 0x14: /* EMUX */
        s->emux = value;
        break;
    case 0x18: /* USTAT */
        s->ustat &= ~value;
        break;
    case 0x20: /* SSPRI */
        s->sspri = value;
        break;
    case 0x28: /* PSSI */
        hw_error("Not implemented:  ADC sample initiate\n");
        break;
    case 0x30: /* SAC */
        s->sac = value;
        break;
    default:
        hw_error("stellaris_adc_write: Bad offset 0x%x\n", (int)offset);
    }
    stellaris_adc_update(s);
}

static const MemoryRegionOps stellaris_adc_ops = {
    .read = stellaris_adc_read,
    .write = stellaris_adc_write,
    .endianness = DEVICE_NATIVE_ENDIAN,
};

static const VMStateDescription vmstate_stellaris_adc = {
    .name = "stellaris_adc",
    .version_id = 1,
    .minimum_version_id = 1,
    .minimum_version_id_old = 1,
    .fields      = (VMStateField[]) {
        VMSTATE_UINT32(actss, stellaris_adc_state),
        VMSTATE_UINT32(ris, stellaris_adc_state),
        VMSTATE_UINT32(im, stellaris_adc_state),
        VMSTATE_UINT32(emux, stellaris_adc_state),
        VMSTATE_UINT32(ostat, stellaris_adc_state),
        VMSTATE_UINT32(ustat, stellaris_adc_state),
        VMSTATE_UINT32(sspri, stellaris_adc_state),
        VMSTATE_UINT32(sac, stellaris_adc_state),
        VMSTATE_UINT32(fifo[0].state, stellaris_adc_state),
        VMSTATE_UINT32_ARRAY(fifo[0].data, stellaris_adc_state, 16),
        VMSTATE_UINT32(ssmux[0], stellaris_adc_state),
        VMSTATE_UINT32(ssctl[0], stellaris_adc_state),
        VMSTATE_UINT32(fifo[1].state, stellaris_adc_state),
        VMSTATE_UINT32_ARRAY(fifo[1].data, stellaris_adc_state, 16),
        VMSTATE_UINT32(ssmux[1], stellaris_adc_state),
        VMSTATE_UINT32(ssctl[1], stellaris_adc_state),
        VMSTATE_UINT32(fifo[2].state, stellaris_adc_state),
        VMSTATE_UINT32_ARRAY(fifo[2].data, stellaris_adc_state, 16),
        VMSTATE_UINT32(ssmux[2], stellaris_adc_state),
        VMSTATE_UINT32(ssctl[2], stellaris_adc_state),
        VMSTATE_UINT32(fifo[3].state, stellaris_adc_state),
        VMSTATE_UINT32_ARRAY(fifo[3].data, stellaris_adc_state, 16),
        VMSTATE_UINT32(ssmux[3], stellaris_adc_state),
        VMSTATE_UINT32(ssctl[3], stellaris_adc_state),
        VMSTATE_UINT32(noise, stellaris_adc_state),
        VMSTATE_END_OF_LIST()
    }
};

static int stellaris_adc_init(SysBusDevice *sbd)
{
    DeviceState *dev = DEVICE(sbd);
    stellaris_adc_state *s = STELLARIS_ADC(dev);
    int n;

    for (n = 0; n < 4; n++) {
        sysbus_init_irq(sbd, &s->irq[n]);
    }

    memory_region_init_io(&s->iomem, OBJECT(s), &stellaris_adc_ops, s,
                          "adc", 0x1000);
    sysbus_init_mmio(sbd, &s->iomem);
    stellaris_adc_reset(s);
    qdev_init_gpio_in(dev, stellaris_adc_trigger, 1);
    vmstate_register(dev, -1, &vmstate_stellaris_adc, s);
    return 0;
}

/* Board init.  */
static stellaris_board_info stellaris_boards[] = {
  { "LM3S811EVB",
    0,
    0x0032000e,
    0x001f001f, /* dc0 */
    0x001132bf,
    0x01071013,
    0x3f0f01ff,
    0x0000001f,
    BP_OLED_I2C
  },
  { "LM3S6965EVB",
    0x10010002,
    0x1073402e,
    0x00ff007f, /* dc0 */
    0x001133ff,
    0x030f5317,
    0x0f0f87ff,
    0x5000007f,
    BP_OLED_SSI | BP_GAMEPAD
  }
};

static void stellaris_init(const char *kernel_filename, const char *cpu_model,
                           stellaris_board_info *board)
{
    static const int uart_irq[] = {5, 6, 33, 34};
    static const int timer_irq[] = {19, 21, 23, 35};
    static const uint32_t gpio_addr[7] =
      { 0x40004000, 0x40005000, 0x40006000, 0x40007000,
        0x40024000, 0x40025000, 0x40026000};
    static const int gpio_irq[7] = {0, 1, 2, 3, 4, 30, 31};

    MemoryRegion *address_space_mem = get_system_memory();
    qemu_irq *pic;
    DeviceState *gpio_dev[7];
    qemu_irq gpio_in[7][8];
    qemu_irq gpio_out[7][8];
    qemu_irq adc;
    int sram_size;
    int flash_size;
    i2c_bus *i2c;
    DeviceState *dev;
    int i;
    int j;

    flash_size = ((board->dc0 & 0xffff) + 1) << 1;
    sram_size = (board->dc0 >> 18) + 1;
    pic = armv7m_init(address_space_mem,
                      flash_size, sram_size, kernel_filename, cpu_model);

    if (board->dc1 & (1 << 16)) {
        dev = sysbus_create_varargs(TYPE_STELLARIS_ADC, 0x40038000,
                                    pic[14], pic[15], pic[16], pic[17], NULL);
        adc = qdev_get_gpio_in(dev, 0);
    } else {
        adc = NULL;
    }
    for (i = 0; i < 4; i++) {
        if (board->dc2 & (0x10000 << i)) {
            dev = sysbus_create_simple(TYPE_STELLARIS_GPTM,
                                       0x40030000 + i * 0x1000,
                                       pic[timer_irq[i]]);
            /* TODO: This is incorrect, but we get away with it because
               the ADC output is only ever pulsed.  */
            qdev_connect_gpio_out(dev, 0, adc);
        }
    }

    stellaris_sys_init(0x400fe000, pic[28], board, nd_table[0].macaddr.a);

    for (i = 0; i < 7; i++) {
        if (board->dc4 & (1 << i)) {
            gpio_dev[i] = sysbus_create_simple("pl061_luminary", gpio_addr[i],
                                               pic[gpio_irq[i]]);
            for (j = 0; j < 8; j++) {
                gpio_in[i][j] = qdev_get_gpio_in(gpio_dev[i], j);
                gpio_out[i][j] = NULL;
            }
        }
    }

    if (board->dc2 & (1 << 12)) {
        dev = sysbus_create_simple(TYPE_STELLARIS_I2C, 0x40020000, pic[8]);
        i2c = (i2c_bus *)qdev_get_child_bus(dev, "i2c");
        if (board->peripherals & BP_OLED_I2C) {
            i2c_create_slave(i2c, "ssd0303", 0x3d);
        }
    }

    for (i = 0; i < 4; i++) {
        if (board->dc2 & (1 << i)) {
            sysbus_create_simple("pl011_luminary", 0x4000c000 + i * 0x1000,
                                 pic[uart_irq[i]]);
        }
    }
    if (board->dc2 & (1 << 4)) {
        dev = sysbus_create_simple("pl022", 0x40008000, pic[7]);
        if (board->peripherals & BP_OLED_SSI) {
            void *bus;
            DeviceState *sddev;
            DeviceState *ssddev;

            /* Some boards have both an OLED controller and SD card connected to
             * the same SSI port, with the SD card chip select connected to a
             * GPIO pin.  Technically the OLED chip select is connected to the
             * SSI Fss pin.  We do not bother emulating that as both devices
             * should never be selected simultaneously, and our OLED controller
             * ignores stray 0xff commands that occur when deselecting the SD
             * card.
             */
            bus = qdev_get_child_bus(dev, "ssi");

            sddev = ssi_create_slave(bus, "ssi-sd");
            ssddev = ssi_create_slave(bus, "ssd0323");
            gpio_out[GPIO_D][0] = qemu_irq_split(qdev_get_gpio_in(sddev, 0),
                                                 qdev_get_gpio_in(ssddev, 0));
            gpio_out[GPIO_C][7] = qdev_get_gpio_in(ssddev, 1);

            /* Make sure the select pin is high.  */
            qemu_irq_raise(gpio_out[GPIO_D][0]);
        }
    }
    if (board->dc4 & (1 << 28)) {
        DeviceState *enet;

        qemu_check_nic_model(&nd_table[0], "stellaris");

        enet = qdev_create(NULL, "stellaris_enet");
        qdev_set_nic_properties(enet, &nd_table[0]);
        qdev_init_nofail(enet);
        sysbus_mmio_map(SYS_BUS_DEVICE(enet), 0, 0x40048000);
        sysbus_connect_irq(SYS_BUS_DEVICE(enet), 0, pic[42]);
    }
    if (board->peripherals & BP_GAMEPAD) {
        qemu_irq gpad_irq[5];
        static const int gpad_keycode[5] = { 0xc8, 0xd0, 0xcb, 0xcd, 0x1d };

        gpad_irq[0] = qemu_irq_invert(gpio_in[GPIO_E][0]); /* up */
        gpad_irq[1] = qemu_irq_invert(gpio_in[GPIO_E][1]); /* down */
        gpad_irq[2] = qemu_irq_invert(gpio_in[GPIO_E][2]); /* left */
        gpad_irq[3] = qemu_irq_invert(gpio_in[GPIO_E][3]); /* right */
        gpad_irq[4] = qemu_irq_invert(gpio_in[GPIO_F][1]); /* select */

        stellaris_gamepad_init(5, gpad_irq, gpad_keycode);
    }
    for (i = 0; i < 7; i++) {
        if (board->dc4 & (1 << i)) {
            for (j = 0; j < 8; j++) {
                if (gpio_out[i][j]) {
                    qdev_connect_gpio_out(gpio_dev[i], j, gpio_out[i][j]);
                }
            }
        }
    }
}

/* FIXME: Figure out how to generate these from stellaris_boards.  */
static void lm3s811evb_init(QEMUMachineInitArgs *args)
{
    const char *cpu_model = args->cpu_model;
    const char *kernel_filename = args->kernel_filename;
    stellaris_init(kernel_filename, cpu_model, &stellaris_boards[0]);
}

static void lm3s6965evb_init(QEMUMachineInitArgs *args)
{
    const char *cpu_model = args->cpu_model;
    const char *kernel_filename = args->kernel_filename;
    stellaris_init(kernel_filename, cpu_model, &stellaris_boards[1]);
}

static QEMUMachine lm3s811evb_machine = {
    .name = "lm3s811evb",
    .desc = "Stellaris LM3S811EVB",
    .init = lm3s811evb_init,
    DEFAULT_MACHINE_OPTIONS,
};

static QEMUMachine lm3s6965evb_machine = {
    .name = "lm3s6965evb",
    .desc = "Stellaris LM3S6965EVB",
    .init = lm3s6965evb_init,
    DEFAULT_MACHINE_OPTIONS,
};

static void stellaris_machine_init(void)
{
    qemu_register_machine(&lm3s811evb_machine);
    qemu_register_machine(&lm3s6965evb_machine);
}

machine_init(stellaris_machine_init);

static void stellaris_i2c_class_init(ObjectClass *klass, void *data)
{
    SysBusDeviceClass *sdc = SYS_BUS_DEVICE_CLASS(klass);

    sdc->init = stellaris_i2c_init;
}

static const TypeInfo stellaris_i2c_info = {
    .name          = TYPE_STELLARIS_I2C,
    .parent        = TYPE_SYS_BUS_DEVICE,
    .instance_size = sizeof(stellaris_i2c_state),
    .class_init    = stellaris_i2c_class_init,
};

static void stellaris_gptm_class_init(ObjectClass *klass, void *data)
{
    SysBusDeviceClass *sdc = SYS_BUS_DEVICE_CLASS(klass);

    sdc->init = stellaris_gptm_init;
}

static const TypeInfo stellaris_gptm_info = {
    .name          = TYPE_STELLARIS_GPTM,
    .parent        = TYPE_SYS_BUS_DEVICE,
    .instance_size = sizeof(gptm_state),
    .class_init    = stellaris_gptm_class_init,
};

static void stellaris_adc_class_init(ObjectClass *klass, void *data)
{
    SysBusDeviceClass *sdc = SYS_BUS_DEVICE_CLASS(klass);

    sdc->init = stellaris_adc_init;
}

static const TypeInfo stellaris_adc_info = {
    .name          = TYPE_STELLARIS_ADC,
    .parent        = TYPE_SYS_BUS_DEVICE,
    .instance_size = sizeof(stellaris_adc_state),
    .class_init    = stellaris_adc_class_init,
};

static void stellaris_register_types(void)
{
    type_register_static(&stellaris_i2c_info);
    type_register_static(&stellaris_gptm_info);
    type_register_static(&stellaris_adc_info);
}

type_init(stellaris_register_types)
