qemu/hw/i2c.c
Markus Armbruster e23a1b33b5 New qdev_init_nofail()
Like qdev_init(), but terminate program via hw_error() instead of
returning an error value.

Use it instead of qdev_init() where terminating the program on failure
is okay, either because it's during machine construction, or because
we know that failure can't happen.

Because relying in the latter is somewhat unclean, and the former is
not always obvious, it would be nice to go back to qdev_init() in the
not-so-obvious cases, only with proper error handling.  I'm leaving
that for another day, because it involves making sure that error
values are properly checked by all callers.

Patchworks-ID: 35168
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2009-10-07 08:54:54 -05:00

195 lines
4.2 KiB
C

/*
* 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) {
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);
}
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;
}