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/*
* 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;
int saved_address;
};
static struct BusInfo i2c_bus_info = {
.name = "I2C",
.size = sizeof(i2c_bus),
};
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(DeviceState *parent, const char *name)
{
i2c_bus *bus;
bus = FROM_QBUS(i2c_bus, qbus_create(&i2c_bus_info, parent, name));
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)
{
DeviceState *qdev;
i2c_slave *slave = NULL;
LIST_FOREACH(qdev, &bus->qbus.children, sibling) {
slave = I2C_SLAVE_FROM_QDEV(qdev);
if (slave->address == address)
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);
}
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 = FROM_QBUS(i2c_bus, qdev_get_parent_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, DeviceInfo *base)
{
I2CSlaveInfo *info = container_of(base, I2CSlaveInfo, qdev);
i2c_slave *s = I2C_SLAVE_FROM_QDEV(dev);
s->info = info;
s->address = qdev_get_prop_int(dev, "address", 0);
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, int addr)
{
DeviceState *dev;
dev = qdev_create(&bus->qbus, name);
qdev_set_prop_int(dev, "address", addr);
qdev_init(dev);
return dev;
}
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