Archipelago » qemu

/*

 * QEMU I2C bus interface.

 *

 * Copyright (c) 2007 CodeSourcery.

 * Written by Paul Brook

 *

 * This code is licenced under the LGPL.

 */

#include "i2c.h"

struct i2c_bus

{

    BusState qbus;

    i2c_slave *current_dev;

    i2c_slave *dev;

    uint8_t saved_address;

};

static struct BusInfo i2c_bus_info = {

    .name = "I2C",

    .size = sizeof(i2c_bus),

    .props = (Property[]) {

        DEFINE_PROP_UINT8("address", struct i2c_slave, address, 0),

        DEFINE_PROP_END_OF_LIST(),

    }

};

static void i2c_bus_pre_save(void *opaque)

{

    i2c_bus *bus = opaque;

    bus->saved_address = bus->current_dev ? bus->current_dev->address : -1;

}

static int i2c_bus_post_load(void *opaque, int version_id)

{

    i2c_bus *bus = opaque;

    /* The bus is loaded before attached devices, so load and save the

       current device id.  Devices will check themselves as loaded.  */

    bus->current_dev = NULL;

    return 0;

}

static const VMStateDescription vmstate_i2c_bus = {

    .name = "i2c_bus",

    .version_id = 1,

    .minimum_version_id = 1,

    .minimum_version_id_old = 1,

    .pre_save = i2c_bus_pre_save,

    .post_load = i2c_bus_post_load,

    .fields      = (VMStateField []) {

        VMSTATE_UINT8(saved_address, i2c_bus),

        VMSTATE_END_OF_LIST()

    }

};

/* Create a new I2C bus.  */

i2c_bus *i2c_init_bus(DeviceState *parent, const char *name)

{

    i2c_bus *bus;

    bus = FROM_QBUS(i2c_bus, qbus_create(&i2c_bus_info, parent, name));

    vmstate_register(-1, &vmstate_i2c_bus, bus);

    return bus;

}

void i2c_set_slave_address(i2c_slave *dev, uint8_t address)

{

    dev->address = address;

}

/* Return nonzero if bus is busy.  */

int i2c_bus_busy(i2c_bus *bus)

{

    return bus->current_dev != NULL;

}

/* Returns non-zero if the address is not valid.  */

/* TODO: Make this handle multiple masters.  */

int i2c_start_transfer(i2c_bus *bus, uint8_t address, int recv)

{

    DeviceState *qdev;

    i2c_slave *slave = NULL;

    QLIST_FOREACH(qdev, &bus->qbus.children, sibling) {

        i2c_slave *candidate = I2C_SLAVE_FROM_QDEV(qdev);

        if (candidate->address == address) {

            slave = candidate;

            break;

        }

    }

    if (!slave)

        return 1;

    /* If the bus is already busy, assume this is a repeated

       start condition.  */

    bus->current_dev = slave;

    slave->info->event(slave, recv ? I2C_START_RECV : I2C_START_SEND);

    return 0;

}

void i2c_end_transfer(i2c_bus *bus)

{

    i2c_slave *dev = bus->current_dev;

    if (!dev)

        return;

    dev->info->event(dev, I2C_FINISH);

    bus->current_dev = NULL;

}

int i2c_send(i2c_bus *bus, uint8_t data)

{

    i2c_slave *dev = bus->current_dev;

    if (!dev)

        return -1;

    return dev->info->send(dev, data);

}

int i2c_recv(i2c_bus *bus)

{

    i2c_slave *dev = bus->current_dev;

    if (!dev)

        return -1;

    return dev->info->recv(dev);

}

void i2c_nack(i2c_bus *bus)

{

    i2c_slave *dev = bus->current_dev;

    if (!dev)

        return;

    dev->info->event(dev, I2C_NACK);

}

static int i2c_slave_post_load(void *opaque, int version_id)

{

    i2c_slave *dev = opaque;

    i2c_bus *bus;

    bus = FROM_QBUS(i2c_bus, qdev_get_parent_bus(&dev->qdev));

    if (bus->saved_address == dev->address) {

        bus->current_dev = dev;

    }

    return 0;

}

const VMStateDescription vmstate_i2c_slave = {

    .name = "i2c_slave",

    .version_id = 1,

    .minimum_version_id = 1,

    .minimum_version_id_old = 1,

    .post_load = i2c_slave_post_load,

    .fields      = (VMStateField []) {

        VMSTATE_UINT8(address, i2c_slave),

        VMSTATE_END_OF_LIST()

    }

};

static int i2c_slave_qdev_init(DeviceState *dev, DeviceInfo *base)

{

    I2CSlaveInfo *info = container_of(base, I2CSlaveInfo, qdev);

    i2c_slave *s = I2C_SLAVE_FROM_QDEV(dev);

    s->info = info;

    return info->init(s);

}

void i2c_register_slave(I2CSlaveInfo *info)

{

    assert(info->qdev.size >= sizeof(i2c_slave));

    info->qdev.init = i2c_slave_qdev_init;

    info->qdev.bus_info = &i2c_bus_info;

    qdev_register(&info->qdev);

}

DeviceState *i2c_create_slave(i2c_bus *bus, const char *name, uint8_t addr)

{

    DeviceState *dev;

    dev = qdev_create(&bus->qbus, name);

    qdev_prop_set_uint8(dev, "address", addr);

    qdev_init_nofail(dev);

    return dev;

}