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1 | /* | |
2 | * QEMU I2C bus interface. | |
3 | * | |
4 | * Copyright (c) 2007 CodeSourcery. | |
5 | * Written by Paul Brook | |
6 | * | |
7 | * This code is licensed under the LGPL. | |
8 | */ | |
9 | ||
10 | #include "hw/i2c.h" | |
11 | ||
12 | struct i2c_bus | |
13 | { | |
14 | BusState qbus; | |
15 | I2CSlave *current_dev; | |
16 | I2CSlave *dev; | |
17 | uint8_t saved_address; | |
18 | }; | |
19 | ||
20 | static Property i2c_props[] = { | |
21 | DEFINE_PROP_UINT8("address", struct I2CSlave, address, 0), | |
22 | DEFINE_PROP_END_OF_LIST(), | |
23 | }; | |
24 | ||
25 | #define TYPE_I2C_BUS "i2c-bus" | |
26 | #define I2C_BUS(obj) OBJECT_CHECK(i2c_bus, (obj), TYPE_I2C_BUS) | |
27 | ||
28 | static const TypeInfo i2c_bus_info = { | |
29 | .name = TYPE_I2C_BUS, | |
30 | .parent = TYPE_BUS, | |
31 | .instance_size = sizeof(i2c_bus), | |
32 | }; | |
33 | ||
34 | static void i2c_bus_pre_save(void *opaque) | |
35 | { | |
36 | i2c_bus *bus = opaque; | |
37 | ||
38 | bus->saved_address = bus->current_dev ? bus->current_dev->address : -1; | |
39 | } | |
40 | ||
41 | static int i2c_bus_post_load(void *opaque, int version_id) | |
42 | { | |
43 | i2c_bus *bus = opaque; | |
44 | ||
45 | /* The bus is loaded before attached devices, so load and save the | |
46 | current device id. Devices will check themselves as loaded. */ | |
47 | bus->current_dev = NULL; | |
48 | return 0; | |
49 | } | |
50 | ||
51 | static const VMStateDescription vmstate_i2c_bus = { | |
52 | .name = "i2c_bus", | |
53 | .version_id = 1, | |
54 | .minimum_version_id = 1, | |
55 | .minimum_version_id_old = 1, | |
56 | .pre_save = i2c_bus_pre_save, | |
57 | .post_load = i2c_bus_post_load, | |
58 | .fields = (VMStateField []) { | |
59 | VMSTATE_UINT8(saved_address, i2c_bus), | |
60 | VMSTATE_END_OF_LIST() | |
61 | } | |
62 | }; | |
63 | ||
64 | /* Create a new I2C bus. */ | |
65 | i2c_bus *i2c_init_bus(DeviceState *parent, const char *name) | |
66 | { | |
67 | i2c_bus *bus; | |
68 | ||
69 | bus = FROM_QBUS(i2c_bus, qbus_create(TYPE_I2C_BUS, parent, name)); | |
70 | vmstate_register(NULL, -1, &vmstate_i2c_bus, bus); | |
71 | return bus; | |
72 | } | |
73 | ||
74 | void i2c_set_slave_address(I2CSlave *dev, uint8_t address) | |
75 | { | |
76 | dev->address = address; | |
77 | } | |
78 | ||
79 | /* Return nonzero if bus is busy. */ | |
80 | int i2c_bus_busy(i2c_bus *bus) | |
81 | { | |
82 | return bus->current_dev != NULL; | |
83 | } | |
84 | ||
85 | /* Returns non-zero if the address is not valid. */ | |
86 | /* TODO: Make this handle multiple masters. */ | |
87 | int i2c_start_transfer(i2c_bus *bus, uint8_t address, int recv) | |
88 | { | |
89 | BusChild *kid; | |
90 | I2CSlave *slave = NULL; | |
91 | I2CSlaveClass *sc; | |
92 | ||
93 | QTAILQ_FOREACH(kid, &bus->qbus.children, sibling) { | |
94 | DeviceState *qdev = kid->child; | |
95 | I2CSlave *candidate = I2C_SLAVE(qdev); | |
96 | if (candidate->address == address) { | |
97 | slave = candidate; | |
98 | break; | |
99 | } | |
100 | } | |
101 | ||
102 | if (!slave) { | |
103 | return 1; | |
104 | } | |
105 | ||
106 | sc = I2C_SLAVE_GET_CLASS(slave); | |
107 | /* If the bus is already busy, assume this is a repeated | |
108 | start condition. */ | |
109 | bus->current_dev = slave; | |
110 | if (sc->event) { | |
111 | sc->event(slave, recv ? I2C_START_RECV : I2C_START_SEND); | |
112 | } | |
113 | return 0; | |
114 | } | |
115 | ||
116 | void i2c_end_transfer(i2c_bus *bus) | |
117 | { | |
118 | I2CSlave *dev = bus->current_dev; | |
119 | I2CSlaveClass *sc; | |
120 | ||
121 | if (!dev) { | |
122 | return; | |
123 | } | |
124 | ||
125 | sc = I2C_SLAVE_GET_CLASS(dev); | |
126 | if (sc->event) { | |
127 | sc->event(dev, I2C_FINISH); | |
128 | } | |
129 | ||
130 | bus->current_dev = NULL; | |
131 | } | |
132 | ||
133 | int i2c_send(i2c_bus *bus, uint8_t data) | |
134 | { | |
135 | I2CSlave *dev = bus->current_dev; | |
136 | I2CSlaveClass *sc; | |
137 | ||
138 | if (!dev) { | |
139 | return -1; | |
140 | } | |
141 | ||
142 | sc = I2C_SLAVE_GET_CLASS(dev); | |
143 | if (sc->send) { | |
144 | return sc->send(dev, data); | |
145 | } | |
146 | ||
147 | return -1; | |
148 | } | |
149 | ||
150 | int i2c_recv(i2c_bus *bus) | |
151 | { | |
152 | I2CSlave *dev = bus->current_dev; | |
153 | I2CSlaveClass *sc; | |
154 | ||
155 | if (!dev) { | |
156 | return -1; | |
157 | } | |
158 | ||
159 | sc = I2C_SLAVE_GET_CLASS(dev); | |
160 | if (sc->recv) { | |
161 | return sc->recv(dev); | |
162 | } | |
163 | ||
164 | return -1; | |
165 | } | |
166 | ||
167 | void i2c_nack(i2c_bus *bus) | |
168 | { | |
169 | I2CSlave *dev = bus->current_dev; | |
170 | I2CSlaveClass *sc; | |
171 | ||
172 | if (!dev) { | |
173 | return; | |
174 | } | |
175 | ||
176 | sc = I2C_SLAVE_GET_CLASS(dev); | |
177 | if (sc->event) { | |
178 | sc->event(dev, I2C_NACK); | |
179 | } | |
180 | } | |
181 | ||
182 | static int i2c_slave_post_load(void *opaque, int version_id) | |
183 | { | |
184 | I2CSlave *dev = opaque; | |
185 | i2c_bus *bus; | |
186 | bus = FROM_QBUS(i2c_bus, qdev_get_parent_bus(&dev->qdev)); | |
187 | if (bus->saved_address == dev->address) { | |
188 | bus->current_dev = dev; | |
189 | } | |
190 | return 0; | |
191 | } | |
192 | ||
193 | const VMStateDescription vmstate_i2c_slave = { | |
194 | .name = "I2CSlave", | |
195 | .version_id = 1, | |
196 | .minimum_version_id = 1, | |
197 | .minimum_version_id_old = 1, | |
198 | .post_load = i2c_slave_post_load, | |
199 | .fields = (VMStateField []) { | |
200 | VMSTATE_UINT8(address, I2CSlave), | |
201 | VMSTATE_END_OF_LIST() | |
202 | } | |
203 | }; | |
204 | ||
205 | static int i2c_slave_qdev_init(DeviceState *dev) | |
206 | { | |
207 | I2CSlave *s = I2C_SLAVE(dev); | |
208 | I2CSlaveClass *sc = I2C_SLAVE_GET_CLASS(s); | |
209 | ||
210 | return sc->init(s); | |
211 | } | |
212 | ||
213 | DeviceState *i2c_create_slave(i2c_bus *bus, const char *name, uint8_t addr) | |
214 | { | |
215 | DeviceState *dev; | |
216 | ||
217 | dev = qdev_create(&bus->qbus, name); | |
218 | qdev_prop_set_uint8(dev, "address", addr); | |
219 | qdev_init_nofail(dev); | |
220 | return dev; | |
221 | } | |
222 | ||
223 | static void i2c_slave_class_init(ObjectClass *klass, void *data) | |
224 | { | |
225 | DeviceClass *k = DEVICE_CLASS(klass); | |
226 | k->init = i2c_slave_qdev_init; | |
227 | k->bus_type = TYPE_I2C_BUS; | |
228 | k->props = i2c_props; | |
229 | } | |
230 | ||
231 | static const TypeInfo i2c_slave_type_info = { | |
232 | .name = TYPE_I2C_SLAVE, | |
233 | .parent = TYPE_DEVICE, | |
234 | .instance_size = sizeof(I2CSlave), | |
235 | .abstract = true, | |
236 | .class_size = sizeof(I2CSlaveClass), | |
237 | .class_init = i2c_slave_class_init, | |
238 | }; | |
239 | ||
240 | static void i2c_slave_register_types(void) | |
241 | { | |
242 | type_register_static(&i2c_bus_info); | |
243 | type_register_static(&i2c_slave_type_info); | |
244 | } | |
245 | ||
246 | type_init(i2c_slave_register_types) |