diff options
Diffstat (limited to 'hw/i2c/core.c')
| -rw-r--r-- | hw/i2c/core.c | 246 |
1 files changed, 246 insertions, 0 deletions
diff --git a/hw/i2c/core.c b/hw/i2c/core.c new file mode 100644 index 0000000000..0c4fc1dbaa --- /dev/null +++ b/hw/i2c/core.c @@ -0,0 +1,246 @@ +/* + * QEMU I2C bus interface. + * + * Copyright (c) 2007 CodeSourcery. + * Written by Paul Brook + * + * This code is licensed under the LGPL. + */ + +#include "hw/i2c/i2c.h" + +struct i2c_bus +{ + BusState qbus; + I2CSlave *current_dev; + I2CSlave *dev; + uint8_t saved_address; +}; + +static Property i2c_props[] = { + DEFINE_PROP_UINT8("address", struct I2CSlave, address, 0), + DEFINE_PROP_END_OF_LIST(), +}; + +#define TYPE_I2C_BUS "i2c-bus" +#define I2C_BUS(obj) OBJECT_CHECK(i2c_bus, (obj), TYPE_I2C_BUS) + +static const TypeInfo i2c_bus_info = { + .name = TYPE_I2C_BUS, + .parent = TYPE_BUS, + .instance_size = sizeof(i2c_bus), +}; + +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(TYPE_I2C_BUS, parent, name)); + vmstate_register(NULL, -1, &vmstate_i2c_bus, bus); + return bus; +} + +void i2c_set_slave_address(I2CSlave *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) +{ + BusChild *kid; + I2CSlave *slave = NULL; + I2CSlaveClass *sc; + + QTAILQ_FOREACH(kid, &bus->qbus.children, sibling) { + DeviceState *qdev = kid->child; + I2CSlave *candidate = I2C_SLAVE(qdev); + if (candidate->address == address) { + slave = candidate; + break; + } + } + + if (!slave) { + return 1; + } + + sc = I2C_SLAVE_GET_CLASS(slave); + /* If the bus is already busy, assume this is a repeated + start condition. */ + bus->current_dev = slave; + if (sc->event) { + sc->event(slave, recv ? I2C_START_RECV : I2C_START_SEND); + } + return 0; +} + +void i2c_end_transfer(i2c_bus *bus) +{ + I2CSlave *dev = bus->current_dev; + I2CSlaveClass *sc; + + if (!dev) { + return; + } + + sc = I2C_SLAVE_GET_CLASS(dev); + if (sc->event) { + sc->event(dev, I2C_FINISH); + } + + bus->current_dev = NULL; +} + +int i2c_send(i2c_bus *bus, uint8_t data) +{ + I2CSlave *dev = bus->current_dev; + I2CSlaveClass *sc; + + if (!dev) { + return -1; + } + + sc = I2C_SLAVE_GET_CLASS(dev); + if (sc->send) { + return sc->send(dev, data); + } + + return -1; +} + +int i2c_recv(i2c_bus *bus) +{ + I2CSlave *dev = bus->current_dev; + I2CSlaveClass *sc; + + if (!dev) { + return -1; + } + + sc = I2C_SLAVE_GET_CLASS(dev); + if (sc->recv) { + return sc->recv(dev); + } + + return -1; +} + +void i2c_nack(i2c_bus *bus) +{ + I2CSlave *dev = bus->current_dev; + I2CSlaveClass *sc; + + if (!dev) { + return; + } + + sc = I2C_SLAVE_GET_CLASS(dev); + if (sc->event) { + sc->event(dev, I2C_NACK); + } +} + +static int i2c_slave_post_load(void *opaque, int version_id) +{ + I2CSlave *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 = "I2CSlave", + .version_id = 1, + .minimum_version_id = 1, + .minimum_version_id_old = 1, + .post_load = i2c_slave_post_load, + .fields = (VMStateField []) { + VMSTATE_UINT8(address, I2CSlave), + VMSTATE_END_OF_LIST() + } +}; + +static int i2c_slave_qdev_init(DeviceState *dev) +{ + I2CSlave *s = I2C_SLAVE(dev); + I2CSlaveClass *sc = I2C_SLAVE_GET_CLASS(s); + + return sc->init(s); +} + +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; +} + +static void i2c_slave_class_init(ObjectClass *klass, void *data) +{ + DeviceClass *k = DEVICE_CLASS(klass); + k->init = i2c_slave_qdev_init; + k->bus_type = TYPE_I2C_BUS; + k->props = i2c_props; +} + +static const TypeInfo i2c_slave_type_info = { + .name = TYPE_I2C_SLAVE, + .parent = TYPE_DEVICE, + .instance_size = sizeof(I2CSlave), + .abstract = true, + .class_size = sizeof(I2CSlaveClass), + .class_init = i2c_slave_class_init, +}; + +static void i2c_slave_register_types(void) +{ + type_register_static(&i2c_bus_info); + type_register_static(&i2c_slave_type_info); +} + +type_init(i2c_slave_register_types) |