blob: 4cf30b2c8638d39bb196ea729f4b28016662aac9 [file] [log] [blame]
/*
* 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 "qapi/error.h"
#include "qemu/module.h"
#include "qemu/main-loop.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 = (const 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_new(TYPE_I2C_BUS, parent, name));
QLIST_INIT(&bus->current_devs);
QSIMPLEQ_INIT(&bus->pending_masters);
vmstate_register_any(NULL, &vmstate_i2c_bus, bus);
return bus;
}
void i2c_slave_set_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) || bus->bh;
}
bool i2c_scan_bus(I2CBus *bus, uint8_t address, bool broadcast,
I2CNodeList *current_devs)
{
BusChild *kid;
QTAILQ_FOREACH(kid, &bus->qbus.children, sibling) {
DeviceState *qdev = kid->child;
I2CSlave *candidate = I2C_SLAVE(qdev);
I2CSlaveClass *sc = I2C_SLAVE_GET_CLASS(candidate);
if (sc->match_and_add(candidate, address, broadcast, current_devs)) {
if (!broadcast) {
return true;
}
}
}
/*
* If broadcast was true, and the list was full or empty, return true. If
* broadcast was false, return false.
*/
return broadcast;
}
/* 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.
*
* @event must be I2C_START_RECV or I2C_START_SEND.
*/
static int i2c_do_start_transfer(I2CBus *bus, uint8_t address,
enum i2c_event event)
{
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)) {
/* Disregard whether devices were found. */
(void)i2c_scan_bus(bus, address, bus->broadcast, &bus->current_devs);
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(event == I2C_START_SEND ? "start" : "start_async",
s->address);
rv = sc->event(s, event);
if (rv && !bus->broadcast) {
if (bus_scanned) {
/* First call, terminate the transfer. */
i2c_end_transfer(bus);
}
return rv;
}
}
}
return 0;
}
int i2c_start_transfer(I2CBus *bus, uint8_t address, bool is_recv)
{
return i2c_do_start_transfer(bus, address, is_recv
? I2C_START_RECV
: I2C_START_SEND);
}
void i2c_bus_master(I2CBus *bus, QEMUBH *bh)
{
I2CPendingMaster *node = g_new(struct I2CPendingMaster, 1);
node->bh = bh;
QSIMPLEQ_INSERT_TAIL(&bus->pending_masters, node, entry);
}
void i2c_schedule_pending_master(I2CBus *bus)
{
I2CPendingMaster *node;
if (i2c_bus_busy(bus)) {
/* someone is already controlling the bus; wait for it to release it */
return;
}
if (QSIMPLEQ_EMPTY(&bus->pending_masters)) {
return;
}
node = QSIMPLEQ_FIRST(&bus->pending_masters);
bus->bh = node->bh;
QSIMPLEQ_REMOVE_HEAD(&bus->pending_masters, entry);
g_free(node);
qemu_bh_schedule(bus->bh);
}
void i2c_bus_release(I2CBus *bus)
{
bus->bh = NULL;
i2c_schedule_pending_master(bus);
}
int i2c_start_recv(I2CBus *bus, uint8_t address)
{
return i2c_do_start_transfer(bus, address, I2C_START_RECV);
}
int i2c_start_send(I2CBus *bus, uint8_t address)
{
return i2c_do_start_transfer(bus, address, I2C_START_SEND);
}
int i2c_start_send_async(I2CBus *bus, uint8_t address)
{
return i2c_do_start_transfer(bus, address, I2C_START_SEND_ASYNC);
}
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(I2CBus *bus, uint8_t data)
{
I2CSlaveClass *sc;
I2CSlave *s;
I2CNode *node;
int ret = 0;
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;
}
int i2c_send_async(I2CBus *bus, uint8_t data)
{
I2CNode *node = QLIST_FIRST(&bus->current_devs);
I2CSlave *slave = node->elt;
I2CSlaveClass *sc = I2C_SLAVE_GET_CLASS(slave);
if (!sc->send_async) {
return -1;
}
trace_i2c_send_async(slave->address, data);
sc->send_async(slave, data);
return 0;
}
uint8_t i2c_recv(I2CBus *bus)
{
uint8_t data = 0xff;
I2CSlaveClass *sc;
I2CSlave *s;
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;
data = sc->recv(s);
trace_i2c_recv(s->address, data);
}
}
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);
}
}
}
void i2c_ack(I2CBus *bus)
{
if (!bus->bh) {
return;
}
trace_i2c_ack();
qemu_bh_schedule(bus->bh);
}
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_new(struct I2CNode, 1);
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 = (const VMStateField[]) {
VMSTATE_UINT8(address, I2CSlave),
VMSTATE_END_OF_LIST()
}
};
I2CSlave *i2c_slave_new(const char *name, uint8_t addr)
{
DeviceState *dev;
dev = qdev_new(name);
qdev_prop_set_uint8(dev, "address", addr);
return I2C_SLAVE(dev);
}
bool i2c_slave_realize_and_unref(I2CSlave *dev, I2CBus *bus, Error **errp)
{
return qdev_realize_and_unref(&dev->qdev, &bus->qbus, errp);
}
I2CSlave *i2c_slave_create_simple(I2CBus *bus, const char *name, uint8_t addr)
{
I2CSlave *dev = i2c_slave_new(name, addr);
i2c_slave_realize_and_unref(dev, bus, &error_abort);
return dev;
}
static bool i2c_slave_match(I2CSlave *candidate, uint8_t address,
bool broadcast, I2CNodeList *current_devs)
{
if ((candidate->address == address) || (broadcast)) {
I2CNode *node = g_new(struct I2CNode, 1);
node->elt = candidate;
QLIST_INSERT_HEAD(current_devs, node, next);
return true;
}
/* Not found and not broadcast. */
return false;
}
static void i2c_slave_class_init(ObjectClass *klass, void *data)
{
DeviceClass *k = DEVICE_CLASS(klass);
I2CSlaveClass *sc = I2C_SLAVE_CLASS(klass);
set_bit(DEVICE_CATEGORY_MISC, k->categories);
k->bus_type = TYPE_I2C_BUS;
device_class_set_props(k, i2c_props);
sc->match_and_add = i2c_slave_match;
}
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)