QLIST_ENTRY(I2CNode) next;
};
+#define I2C_BROADCAST 0x00
+
struct I2CBus
{
BusState qbus;
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;
}
}
}
.pre_save = i2c_bus_pre_save,
.fields = (VMStateField[]) {
VMSTATE_UINT8(saved_address, I2CBus),
- VMSTATE_BOOL(broadcast, I2CBus),
VMSTATE_END_OF_LIST()
}
};
return !QLIST_EMPTY(&bus->current_devs);
}
-/* Returns non-zero if the address is not valid. */
/* 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 == 0x00) {
+ if (address == I2C_BROADCAST) {
/*
* This is a broadcast, the current_devs will be all the devices of the
* bus.
bus->broadcast = true;
}
- 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;
+ /*
+ * 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)) {
}
QLIST_FOREACH(node, &bus->current_devs, next) {
+ int rv;
+
sc = I2C_SLAVE_GET_CLASS(node->elt);
/* If the bus is already busy, assume this is a repeated
start condition. */
+
if (sc->event) {
- sc->event(node->elt, recv ? I2C_START_RECV : I2C_START_SEND);
+ rv = sc->event(node->elt, 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;
I2CSlaveClass *sc;
I2CNode *node, *next;
- if (QLIST_EMPTY(&bus->current_devs)) {
- return;
- }
-
QLIST_FOREACH_SAFE(node, &bus->current_devs, next, next) {
sc = I2C_SLAVE_GET_CLASS(node->elt);
if (sc->event) {
bus->broadcast = false;
}
-int i2c_send(I2CBus *bus, uint8_t data)
+int i2c_send_recv(I2CBus *bus, uint8_t *data, bool send)
{
I2CSlaveClass *sc;
I2CNode *node;
int ret = 0;
- QLIST_FOREACH(node, &bus->current_devs, next) {
- sc = I2C_SLAVE_GET_CLASS(node->elt);
- if (sc->send) {
- ret = ret || sc->send(node->elt, data);
- } else {
- ret = -1;
+ if (send) {
+ QLIST_FOREACH(node, &bus->current_devs, next) {
+ sc = I2C_SLAVE_GET_CLASS(node->elt);
+ if (sc->send) {
+ ret = ret || sc->send(node->elt, *data);
+ } else {
+ ret = -1;
+ }
}
+ return ret ? -1 : 0;
+ } else {
+ if ((QLIST_EMPTY(&bus->current_devs)) || (bus->broadcast)) {
+ return -1;
+ }
+
+ sc = I2C_SLAVE_GET_CLASS(QLIST_FIRST(&bus->current_devs)->elt);
+ if (sc->recv) {
+ ret = sc->recv(QLIST_FIRST(&bus->current_devs)->elt);
+ if (ret < 0) {
+ return ret;
+ } else {
+ *data = ret;
+ return 0;
+ }
+ }
+ return -1;
}
- return ret ? -1 : 0;
}
-int i2c_recv(I2CBus *bus)
+int i2c_send(I2CBus *bus, uint8_t data)
{
- I2CSlaveClass *sc;
+ return i2c_send_recv(bus, &data, true);
+}
- if ((QLIST_EMPTY(&bus->current_devs)) || (bus->broadcast)) {
- return -1;
- }
+int i2c_recv(I2CBus *bus)
+{
+ uint8_t data;
+ int ret = i2c_send_recv(bus, &data, false);
- sc = I2C_SLAVE_GET_CLASS(QLIST_FIRST(&bus->current_devs)->elt);
- if (sc->recv) {
- return sc->recv(QLIST_FIRST(&bus->current_devs)->elt);
- }
- return -1;
+ return ret < 0 ? ret : data;
}
void i2c_nack(I2CBus *bus)
I2CNode *node;
bus = I2C_BUS(qdev_get_parent_bus(DEVICE(dev)));
- if ((bus->saved_address == dev->address) || (bus->broadcast)) {
+ 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);
I2CSlave *s = I2C_SLAVE(dev);
I2CSlaveClass *sc = I2C_SLAVE_GET_CLASS(s);
- return sc->init(s);
+ if (sc->init) {
+ return sc->init(s);
+ }
+
+ return 0;
}
DeviceState *i2c_create_slave(I2CBus *bus, const char *name, uint8_t addr)
projects / qemu.git / blobdiff