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

{

    i2c_slave *current_dev;

    i2c_slave *dev;

    int saved_address;

};

static void i2c_bus_save(QEMUFile *f, void *opaque)

{

    i2c_bus *bus = (i2c_bus *)opaque;

    qemu_put_byte(f, bus->current_dev ? bus->current_dev->address : -1);

}

static int i2c_bus_load(QEMUFile *f, void *opaque, int version_id)

{

    i2c_bus *bus = (i2c_bus *)opaque;

    if (version_id != 1)

        return -EINVAL;

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

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

    bus->saved_address = (int8_t) qemu_get_byte(f);

    bus->current_dev = NULL;

    return 0;

}

/* Create a new I2C bus.  */

i2c_bus *i2c_init_bus(void)

{

    i2c_bus *bus;

    bus = (i2c_bus *)qemu_mallocz(sizeof(i2c_bus));

    register_savevm("i2c_bus", -1, 1, i2c_bus_save, i2c_bus_load, bus);

    return bus;

}

void i2c_set_slave_address(i2c_slave *dev, int 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, int address, int recv)

{

    i2c_slave *dev;

    for (dev = bus->dev; dev; dev = dev->next) {

        if (dev->address == address)

            break;

    }

    if (!dev)

        return 1;

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

       start condition.  */

    bus->current_dev = dev;

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

}

void i2c_slave_save(QEMUFile *f, i2c_slave *dev)

{

    qemu_put_byte(f, dev->address);

}

void i2c_slave_load(QEMUFile *f, i2c_slave *dev)

{

    i2c_bus *bus;

    bus = qdev_get_bus(&dev->qdev);

    dev->address = qemu_get_byte(f);

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

        bus->current_dev = dev;

    }

}

static void i2c_slave_qdev_init(DeviceState *dev, void *opaque)

{

    I2CSlaveInfo *info = opaque;

    i2c_slave *s = I2C_SLAVE_FROM_QDEV(dev);

    s->info = info;

    s->bus = qdev_get_bus(dev);

    s->address = qdev_get_prop_int(dev, "address", 0);

    s->next = s->bus->dev;

    s->bus->dev = s;

    info->init(s);

}

void i2c_register_slave(const char *name, int size, I2CSlaveInfo *info)

{

    assert(size >= sizeof(i2c_slave));

    qdev_register(name, size, i2c_slave_qdev_init, info);

}

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

{

    DeviceState *dev;

    dev = qdev_create(bus, name);

    qdev_set_prop_int(dev, "address", addr);

    qdev_init(dev);

    return dev;

}