migration: pre_save return int
[qemu/ar7.git] / hw / i2c / core.c
blob59068f157eb5eb453690e3fc508e878b67f0bc8d
1 /*
2 * QEMU I2C bus interface.
4 * Copyright (c) 2007 CodeSourcery.
5 * Written by Paul Brook
7 * This code is licensed under the LGPL.
8 */
10 #include "qemu/osdep.h"
11 #include "hw/i2c/i2c.h"
13 typedef struct I2CNode I2CNode;
15 struct I2CNode {
16 I2CSlave *elt;
17 QLIST_ENTRY(I2CNode) next;
20 #define I2C_BROADCAST 0x00
22 struct I2CBus
24 BusState qbus;
25 QLIST_HEAD(, I2CNode) current_devs;
26 uint8_t saved_address;
27 bool broadcast;
30 static Property i2c_props[] = {
31 DEFINE_PROP_UINT8("address", struct I2CSlave, address, 0),
32 DEFINE_PROP_END_OF_LIST(),
35 #define TYPE_I2C_BUS "i2c-bus"
36 #define I2C_BUS(obj) OBJECT_CHECK(I2CBus, (obj), TYPE_I2C_BUS)
38 static const TypeInfo i2c_bus_info = {
39 .name = TYPE_I2C_BUS,
40 .parent = TYPE_BUS,
41 .instance_size = sizeof(I2CBus),
44 static int i2c_bus_pre_save(void *opaque)
46 I2CBus *bus = opaque;
48 bus->saved_address = -1;
49 if (!QLIST_EMPTY(&bus->current_devs)) {
50 if (!bus->broadcast) {
51 bus->saved_address = QLIST_FIRST(&bus->current_devs)->elt->address;
52 } else {
53 bus->saved_address = I2C_BROADCAST;
57 return 0;
60 static const VMStateDescription vmstate_i2c_bus = {
61 .name = "i2c_bus",
62 .version_id = 1,
63 .minimum_version_id = 1,
64 .pre_save = i2c_bus_pre_save,
65 .fields = (VMStateField[]) {
66 VMSTATE_UINT8(saved_address, I2CBus),
67 VMSTATE_END_OF_LIST()
71 /* Create a new I2C bus. */
72 I2CBus *i2c_init_bus(DeviceState *parent, const char *name)
74 I2CBus *bus;
76 bus = I2C_BUS(qbus_create(TYPE_I2C_BUS, parent, name));
77 QLIST_INIT(&bus->current_devs);
78 vmstate_register(NULL, -1, &vmstate_i2c_bus, bus);
79 return bus;
82 void i2c_set_slave_address(I2CSlave *dev, uint8_t address)
84 dev->address = address;
87 /* Return nonzero if bus is busy. */
88 int i2c_bus_busy(I2CBus *bus)
90 return !QLIST_EMPTY(&bus->current_devs);
93 /* TODO: Make this handle multiple masters. */
95 * Start or continue an i2c transaction. When this is called for the
96 * first time or after an i2c_end_transfer(), if it returns an error
97 * the bus transaction is terminated (or really never started). If
98 * this is called after another i2c_start_transfer() without an
99 * intervening i2c_end_transfer(), and it returns an error, the
100 * transaction will not be terminated. The caller must do it.
102 * This corresponds with the way real hardware works. The SMBus
103 * protocol uses a start transfer to switch from write to read mode
104 * without releasing the bus. If that fails, the bus is still
105 * in a transaction.
107 int i2c_start_transfer(I2CBus *bus, uint8_t address, int recv)
109 BusChild *kid;
110 I2CSlaveClass *sc;
111 I2CNode *node;
112 bool bus_scanned = false;
114 if (address == I2C_BROADCAST) {
116 * This is a broadcast, the current_devs will be all the devices of the
117 * bus.
119 bus->broadcast = true;
123 * If there are already devices in the list, that means we are in
124 * the middle of a transaction and we shouldn't rescan the bus.
126 * This happens with any SMBus transaction, even on a pure I2C
127 * device. The interface does a transaction start without
128 * terminating the previous transaction.
130 if (QLIST_EMPTY(&bus->current_devs)) {
131 QTAILQ_FOREACH(kid, &bus->qbus.children, sibling) {
132 DeviceState *qdev = kid->child;
133 I2CSlave *candidate = I2C_SLAVE(qdev);
134 if ((candidate->address == address) || (bus->broadcast)) {
135 node = g_malloc(sizeof(struct I2CNode));
136 node->elt = candidate;
137 QLIST_INSERT_HEAD(&bus->current_devs, node, next);
138 if (!bus->broadcast) {
139 break;
143 bus_scanned = true;
146 if (QLIST_EMPTY(&bus->current_devs)) {
147 return 1;
150 QLIST_FOREACH(node, &bus->current_devs, next) {
151 int rv;
153 sc = I2C_SLAVE_GET_CLASS(node->elt);
154 /* If the bus is already busy, assume this is a repeated
155 start condition. */
157 if (sc->event) {
158 rv = sc->event(node->elt, recv ? I2C_START_RECV : I2C_START_SEND);
159 if (rv && !bus->broadcast) {
160 if (bus_scanned) {
161 /* First call, terminate the transfer. */
162 i2c_end_transfer(bus);
164 return rv;
168 return 0;
171 void i2c_end_transfer(I2CBus *bus)
173 I2CSlaveClass *sc;
174 I2CNode *node, *next;
176 QLIST_FOREACH_SAFE(node, &bus->current_devs, next, next) {
177 sc = I2C_SLAVE_GET_CLASS(node->elt);
178 if (sc->event) {
179 sc->event(node->elt, I2C_FINISH);
181 QLIST_REMOVE(node, next);
182 g_free(node);
184 bus->broadcast = false;
187 int i2c_send_recv(I2CBus *bus, uint8_t *data, bool send)
189 I2CSlaveClass *sc;
190 I2CNode *node;
191 int ret = 0;
193 if (send) {
194 QLIST_FOREACH(node, &bus->current_devs, next) {
195 sc = I2C_SLAVE_GET_CLASS(node->elt);
196 if (sc->send) {
197 ret = ret || sc->send(node->elt, *data);
198 } else {
199 ret = -1;
202 return ret ? -1 : 0;
203 } else {
204 if ((QLIST_EMPTY(&bus->current_devs)) || (bus->broadcast)) {
205 return -1;
208 sc = I2C_SLAVE_GET_CLASS(QLIST_FIRST(&bus->current_devs)->elt);
209 if (sc->recv) {
210 ret = sc->recv(QLIST_FIRST(&bus->current_devs)->elt);
211 if (ret < 0) {
212 return ret;
213 } else {
214 *data = ret;
215 return 0;
218 return -1;
222 int i2c_send(I2CBus *bus, uint8_t data)
224 return i2c_send_recv(bus, &data, true);
227 int i2c_recv(I2CBus *bus)
229 uint8_t data;
230 int ret = i2c_send_recv(bus, &data, false);
232 return ret < 0 ? ret : data;
235 void i2c_nack(I2CBus *bus)
237 I2CSlaveClass *sc;
238 I2CNode *node;
240 if (QLIST_EMPTY(&bus->current_devs)) {
241 return;
244 QLIST_FOREACH(node, &bus->current_devs, next) {
245 sc = I2C_SLAVE_GET_CLASS(node->elt);
246 if (sc->event) {
247 sc->event(node->elt, I2C_NACK);
252 static int i2c_slave_post_load(void *opaque, int version_id)
254 I2CSlave *dev = opaque;
255 I2CBus *bus;
256 I2CNode *node;
258 bus = I2C_BUS(qdev_get_parent_bus(DEVICE(dev)));
259 if ((bus->saved_address == dev->address) ||
260 (bus->saved_address == I2C_BROADCAST)) {
261 node = g_malloc(sizeof(struct I2CNode));
262 node->elt = dev;
263 QLIST_INSERT_HEAD(&bus->current_devs, node, next);
265 return 0;
268 const VMStateDescription vmstate_i2c_slave = {
269 .name = "I2CSlave",
270 .version_id = 1,
271 .minimum_version_id = 1,
272 .post_load = i2c_slave_post_load,
273 .fields = (VMStateField[]) {
274 VMSTATE_UINT8(address, I2CSlave),
275 VMSTATE_END_OF_LIST()
279 static int i2c_slave_qdev_init(DeviceState *dev)
281 I2CSlave *s = I2C_SLAVE(dev);
282 I2CSlaveClass *sc = I2C_SLAVE_GET_CLASS(s);
284 if (sc->init) {
285 return sc->init(s);
288 return 0;
291 DeviceState *i2c_create_slave(I2CBus *bus, const char *name, uint8_t addr)
293 DeviceState *dev;
295 dev = qdev_create(&bus->qbus, name);
296 qdev_prop_set_uint8(dev, "address", addr);
297 qdev_init_nofail(dev);
298 return dev;
301 static void i2c_slave_class_init(ObjectClass *klass, void *data)
303 DeviceClass *k = DEVICE_CLASS(klass);
304 k->init = i2c_slave_qdev_init;
305 set_bit(DEVICE_CATEGORY_MISC, k->categories);
306 k->bus_type = TYPE_I2C_BUS;
307 k->props = i2c_props;
310 static const TypeInfo i2c_slave_type_info = {
311 .name = TYPE_I2C_SLAVE,
312 .parent = TYPE_DEVICE,
313 .instance_size = sizeof(I2CSlave),
314 .abstract = true,
315 .class_size = sizeof(I2CSlaveClass),
316 .class_init = i2c_slave_class_init,
319 static void i2c_slave_register_types(void)
321 type_register_static(&i2c_bus_info);
322 type_register_static(&i2c_slave_type_info);
325 type_init(i2c_slave_register_types)