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/*
* QEMU I2C bus interface.
*
* Copyright (c) 2007 CodeSourcery.
* Written by Paul Brook
*
* This code is licenced under the LGPL.
*/
#include "hw.h"
#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;
}
/* Create a new slave device. */
i2c_slave *i2c_slave_init(i2c_bus *bus, int address, int size)
{
i2c_slave *dev;
if (size < sizeof(i2c_slave))
hw_error("I2C struct too small");
dev = (i2c_slave *)qemu_mallocz(size);
dev->address = address;
dev->next = bus->dev;
bus->dev = dev;
dev->bus = bus;
return dev;
}
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->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->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->send(dev, data);
}
int i2c_recv(i2c_bus *bus)
{
i2c_slave *dev = bus->current_dev;
if (!dev)
return -1;
return dev->recv(dev);
}
void i2c_nack(i2c_bus *bus)
{
i2c_slave *dev = bus->current_dev;
if (!dev)
return;
dev->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)
{
dev->address = qemu_get_byte(f);
if (dev->bus->saved_address == dev->address)
dev->bus->current_dev = dev;
}
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