Archipelago » qemu

/*

 * Maxim MAX1110/1111 ADC chip emulation.

 *

 * Copyright (c) 2006 Openedhand Ltd.

 * Written by Andrzej Zaborowski <balrog@zabor.org>

 *

 * This code is licensed under the GNU GPLv2.

 */

#include "ssi.h"

typedef struct {

    SSISlave ssidev;

    qemu_irq interrupt;

    uint8_t tb1, rb2, rb3;

    int cycle;

    uint8_t input[8];

    int inputs, com;

} MAX111xState;

/* Control-byte bitfields */

#define CB_PD0                (1 << 0)

#define CB_PD1                (1 << 1)

#define CB_SGL                (1 << 2)

#define CB_UNI                (1 << 3)

#define CB_SEL0                (1 << 4)

#define CB_SEL1                (1 << 5)

#define CB_SEL2                (1 << 6)

#define CB_START        (1 << 7)

#define CHANNEL_NUM(v, b0, b1, b2)        \

                        ((((v) >> (2 + (b0))) & 4) |        \

                         (((v) >> (3 + (b1))) & 2) |        \

                         (((v) >> (4 + (b2))) & 1))

static uint32_t max111x_read(MAX111xState *s)

{

    if (!s->tb1)

        return 0;

    switch (s->cycle ++) {

    case 1:

        return s->rb2;

    case 2:

        return s->rb3;

    }

    return 0;

}

/* Interpret a control-byte */

static void max111x_write(MAX111xState *s, uint32_t value)

{

    int measure, chan;

    /* Ignore the value if START bit is zero */

    if (!(value & CB_START))

        return;

    s->cycle = 0;

    if (!(value & CB_PD1)) {

        s->tb1 = 0;

        return;

    }

    s->tb1 = value;

    if (s->inputs == 8)

        chan = CHANNEL_NUM(value, 1, 0, 2);

    else

        chan = CHANNEL_NUM(value & ~CB_SEL0, 0, 1, 2);

    if (value & CB_SGL)

        measure = s->input[chan] - s->com;

    else

        measure = s->input[chan] - s->input[chan ^ 1];

    if (!(value & CB_UNI))

        measure ^= 0x80;

    s->rb2 = (measure >> 2) & 0x3f;

    s->rb3 = (measure << 6) & 0xc0;

    /* FIXME: When should the IRQ be lowered?  */

    qemu_irq_raise(s->interrupt);

}

static uint32_t max111x_transfer(SSISlave *dev, uint32_t value)

{

    MAX111xState *s = FROM_SSI_SLAVE(MAX111xState, dev);

    max111x_write(s, value);

    return max111x_read(s);

}

static const VMStateDescription vmstate_max111x = {

    .name = "max111x",

    .version_id = 0,

    .minimum_version_id = 0,

    .minimum_version_id_old = 0,

    .fields      = (VMStateField[]) {

        VMSTATE_UINT8(tb1, MAX111xState),

        VMSTATE_UINT8(rb2, MAX111xState),

        VMSTATE_UINT8(rb3, MAX111xState),

        VMSTATE_INT32_EQUAL(inputs, MAX111xState),

        VMSTATE_INT32(com, MAX111xState),

        VMSTATE_ARRAY_INT32_UNSAFE(input, MAX111xState, inputs,

                                   vmstate_info_uint8, uint8_t),

        VMSTATE_END_OF_LIST()

    }

};

static int max111x_init(SSISlave *dev, int inputs)

{

    MAX111xState *s = FROM_SSI_SLAVE(MAX111xState, dev);

    qdev_init_gpio_out(&dev->qdev, &s->interrupt, 1);

    s->inputs = inputs;

    /* TODO: add a user interface for setting these */

    s->input[0] = 0xf0;

    s->input[1] = 0xe0;

    s->input[2] = 0xd0;

    s->input[3] = 0xc0;

    s->input[4] = 0xb0;

    s->input[5] = 0xa0;

    s->input[6] = 0x90;

    s->input[7] = 0x80;

    s->com = 0;

    vmstate_register(&dev->qdev, -1, &vmstate_max111x, s);

    return 0;

}

static int max1110_init(SSISlave *dev)

{

    return max111x_init(dev, 8);

}

static int max1111_init(SSISlave *dev)

{

    return max111x_init(dev, 4);

}

void max111x_set_input(DeviceState *dev, int line, uint8_t value)

{

    MAX111xState *s = FROM_SSI_SLAVE(MAX111xState, SSI_SLAVE_FROM_QDEV(dev));

    assert(line >= 0 && line < s->inputs);

    s->input[line] = value;

}

static SSISlaveInfo max1110_info = {

    .qdev.name = "max1110",

    .qdev.size = sizeof(MAX111xState),

    .init = max1110_init,

    .transfer = max111x_transfer

};

static SSISlaveInfo max1111_info = {

    .qdev.name = "max1111",

    .qdev.size = sizeof(MAX111xState),

    .init = max1111_init,

    .transfer = max111x_transfer

};

static void max111x_register_devices(void)

{

    ssi_register_slave(&max1110_info);

    ssi_register_slave(&max1111_info);

}

device_init(max111x_register_devices)