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- /*
- * QEMU I2C bus interface.
- *
- * Copyright (c) 2007 CodeSourcery.
- * Written by Paul Brook
- *
- * This code is licensed under the LGPL.
- */
- #include "qemu/osdep.h"
- #include "hw/i2c/i2c.h"
- #include "hw/qdev-properties.h"
- #include "migration/vmstate.h"
- #include "qemu/module.h"
- #include "trace.h"
- #define I2C_BROADCAST 0x00
- static Property i2c_props[] = {
- DEFINE_PROP_UINT8("address", struct I2CSlave, address, 0),
- DEFINE_PROP_END_OF_LIST(),
- };
- static const TypeInfo i2c_bus_info = {
- .name = TYPE_I2C_BUS,
- .parent = TYPE_BUS,
- .instance_size = sizeof(I2CBus),
- };
- static int i2c_bus_pre_save(void *opaque)
- {
- I2CBus *bus = opaque;
- bus->saved_address = -1;
- if (!QLIST_EMPTY(&bus->current_devs)) {
- if (!bus->broadcast) {
- bus->saved_address = QLIST_FIRST(&bus->current_devs)->elt->address;
- } else {
- bus->saved_address = I2C_BROADCAST;
- }
- }
- return 0;
- }
- static const VMStateDescription vmstate_i2c_bus = {
- .name = "i2c_bus",
- .version_id = 1,
- .minimum_version_id = 1,
- .pre_save = i2c_bus_pre_save,
- .fields = (VMStateField[]) {
- VMSTATE_UINT8(saved_address, I2CBus),
- VMSTATE_END_OF_LIST()
- }
- };
- /* Create a new I2C bus. */
- I2CBus *i2c_init_bus(DeviceState *parent, const char *name)
- {
- I2CBus *bus;
- bus = I2C_BUS(qbus_create(TYPE_I2C_BUS, parent, name));
- QLIST_INIT(&bus->current_devs);
- 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(I2CBus *bus)
- {
- return !QLIST_EMPTY(&bus->current_devs);
- }
- /* TODO: Make this handle multiple masters. */
- /*
- * Start or continue an i2c transaction. When this is called for the
- * first time or after an i2c_end_transfer(), if it returns an error
- * the bus transaction is terminated (or really never started). If
- * this is called after another i2c_start_transfer() without an
- * intervening i2c_end_transfer(), and it returns an error, the
- * transaction will not be terminated. The caller must do it.
- *
- * This corresponds with the way real hardware works. The SMBus
- * protocol uses a start transfer to switch from write to read mode
- * without releasing the bus. If that fails, the bus is still
- * in a transaction.
- */
- int i2c_start_transfer(I2CBus *bus, uint8_t address, int recv)
- {
- BusChild *kid;
- I2CSlaveClass *sc;
- I2CNode *node;
- bool bus_scanned = false;
- if (address == I2C_BROADCAST) {
- /*
- * This is a broadcast, the current_devs will be all the devices of the
- * bus.
- */
- bus->broadcast = true;
- }
- /*
- * If there are already devices in the list, that means we are in
- * the middle of a transaction and we shouldn't rescan the bus.
- *
- * This happens with any SMBus transaction, even on a pure I2C
- * device. The interface does a transaction start without
- * terminating the previous transaction.
- */
- if (QLIST_EMPTY(&bus->current_devs)) {
- QTAILQ_FOREACH(kid, &bus->qbus.children, sibling) {
- DeviceState *qdev = kid->child;
- I2CSlave *candidate = I2C_SLAVE(qdev);
- if ((candidate->address == address) || (bus->broadcast)) {
- node = g_malloc(sizeof(struct I2CNode));
- node->elt = candidate;
- QLIST_INSERT_HEAD(&bus->current_devs, node, next);
- if (!bus->broadcast) {
- break;
- }
- }
- }
- bus_scanned = true;
- }
- if (QLIST_EMPTY(&bus->current_devs)) {
- return 1;
- }
- QLIST_FOREACH(node, &bus->current_devs, next) {
- I2CSlave *s = node->elt;
- int rv;
- sc = I2C_SLAVE_GET_CLASS(s);
- /* If the bus is already busy, assume this is a repeated
- start condition. */
- if (sc->event) {
- trace_i2c_event("start", s->address);
- rv = sc->event(s, recv ? I2C_START_RECV : I2C_START_SEND);
- if (rv && !bus->broadcast) {
- if (bus_scanned) {
- /* First call, terminate the transfer. */
- i2c_end_transfer(bus);
- }
- return rv;
- }
- }
- }
- return 0;
- }
- void i2c_end_transfer(I2CBus *bus)
- {
- I2CSlaveClass *sc;
- I2CNode *node, *next;
- QLIST_FOREACH_SAFE(node, &bus->current_devs, next, next) {
- I2CSlave *s = node->elt;
- sc = I2C_SLAVE_GET_CLASS(s);
- if (sc->event) {
- trace_i2c_event("finish", s->address);
- sc->event(s, I2C_FINISH);
- }
- QLIST_REMOVE(node, next);
- g_free(node);
- }
- bus->broadcast = false;
- }
- int i2c_send_recv(I2CBus *bus, uint8_t *data, bool send)
- {
- I2CSlaveClass *sc;
- I2CSlave *s;
- I2CNode *node;
- int ret = 0;
- if (send) {
- QLIST_FOREACH(node, &bus->current_devs, next) {
- s = node->elt;
- sc = I2C_SLAVE_GET_CLASS(s);
- if (sc->send) {
- trace_i2c_send(s->address, *data);
- ret = ret || sc->send(s, *data);
- } else {
- ret = -1;
- }
- }
- return ret ? -1 : 0;
- } else {
- ret = 0xff;
- if (!QLIST_EMPTY(&bus->current_devs) && !bus->broadcast) {
- sc = I2C_SLAVE_GET_CLASS(QLIST_FIRST(&bus->current_devs)->elt);
- if (sc->recv) {
- s = QLIST_FIRST(&bus->current_devs)->elt;
- ret = sc->recv(s);
- trace_i2c_recv(s->address, ret);
- }
- }
- *data = ret;
- return 0;
- }
- }
- int i2c_send(I2CBus *bus, uint8_t data)
- {
- return i2c_send_recv(bus, &data, true);
- }
- uint8_t i2c_recv(I2CBus *bus)
- {
- uint8_t data = 0xff;
- i2c_send_recv(bus, &data, false);
- return data;
- }
- void i2c_nack(I2CBus *bus)
- {
- I2CSlaveClass *sc;
- I2CNode *node;
- if (QLIST_EMPTY(&bus->current_devs)) {
- return;
- }
- QLIST_FOREACH(node, &bus->current_devs, next) {
- sc = I2C_SLAVE_GET_CLASS(node->elt);
- if (sc->event) {
- trace_i2c_event("nack", node->elt->address);
- sc->event(node->elt, I2C_NACK);
- }
- }
- }
- static int i2c_slave_post_load(void *opaque, int version_id)
- {
- I2CSlave *dev = opaque;
- I2CBus *bus;
- I2CNode *node;
- bus = I2C_BUS(qdev_get_parent_bus(DEVICE(dev)));
- if ((bus->saved_address == dev->address) ||
- (bus->saved_address == I2C_BROADCAST)) {
- node = g_malloc(sizeof(struct I2CNode));
- node->elt = dev;
- QLIST_INSERT_HEAD(&bus->current_devs, node, next);
- }
- return 0;
- }
- const VMStateDescription vmstate_i2c_slave = {
- .name = "I2CSlave",
- .version_id = 1,
- .minimum_version_id = 1,
- .post_load = i2c_slave_post_load,
- .fields = (VMStateField[]) {
- VMSTATE_UINT8(address, I2CSlave),
- VMSTATE_END_OF_LIST()
- }
- };
- DeviceState *i2c_create_slave(I2CBus *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);
- set_bit(DEVICE_CATEGORY_MISC, k->categories);
- 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)
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