hw/i2c/core.c

   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/i2c.h"
  11
  12 struct I2CBus
  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(I2CBus, (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(I2CBus),
  32 };
  33
  34 static void i2c_bus_pre_save(void *opaque)
  35 {
  36     I2CBus *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     I2CBus *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     .pre_save = i2c_bus_pre_save,
  56     .post_load = i2c_bus_post_load,
  57     .fields = (VMStateField[]) {
  58         VMSTATE_UINT8(saved_address, I2CBus),
  59         VMSTATE_END_OF_LIST()
  60     }
  61 };
  62
  63 /* Create a new I2C bus.  */
  64 I2CBus *i2c_init_bus(DeviceState *parent, const char *name)
  65 {
  66     I2CBus *bus;
  67
  68     bus = I2C_BUS(qbus_create(TYPE_I2C_BUS, parent, name));
  69     vmstate_register(NULL, -1, &vmstate_i2c_bus, bus);
  70     return bus;
  71 }
  72
  73 void i2c_set_slave_address(I2CSlave *dev, uint8_t address)
  74 {
  75     dev->address = address;
  76 }
  77
  78 /* Return nonzero if bus is busy.  */
  79 int i2c_bus_busy(I2CBus *bus)
  80 {
  81     return bus->current_dev != NULL;
  82 }
  83
  84 /* Returns non-zero if the address is not valid.  */
  85 /* TODO: Make this handle multiple masters.  */
  86 int i2c_start_transfer(I2CBus *bus, uint8_t address, int recv)
  87 {
  88     BusChild *kid;
  89     I2CSlave *slave = NULL;
  90     I2CSlaveClass *sc;
  91
  92     QTAILQ_FOREACH(kid, &bus->qbus.children, sibling) {
  93         DeviceState *qdev = kid->child;
  94         I2CSlave *candidate = I2C_SLAVE(qdev);
  95         if (candidate->address == address) {
  96             slave = candidate;
  97             break;
  98         }
  99     }
 100
 101     if (!slave) {
 102         return 1;
 103     }
 104
 105     sc = I2C_SLAVE_GET_CLASS(slave);
 106     /* If the bus is already busy, assume this is a repeated
 107        start condition.  */
 108     bus->current_dev = slave;
 109     if (sc->event) {
 110         sc->event(slave, recv ? I2C_START_RECV : I2C_START_SEND);
 111     }
 112     return 0;
 113 }
 114
 115 void i2c_end_transfer(I2CBus *bus)
 116 {
 117     I2CSlave *dev = bus->current_dev;
 118     I2CSlaveClass *sc;
 119
 120     if (!dev) {
 121         return;
 122     }
 123
 124     sc = I2C_SLAVE_GET_CLASS(dev);
 125     if (sc->event) {
 126         sc->event(dev, I2C_FINISH);
 127     }
 128
 129     bus->current_dev = NULL;
 130 }
 131
 132 int i2c_send(I2CBus *bus, uint8_t data)
 133 {
 134     I2CSlave *dev = bus->current_dev;
 135     I2CSlaveClass *sc;
 136
 137     if (!dev) {
 138         return -1;
 139     }
 140
 141     sc = I2C_SLAVE_GET_CLASS(dev);
 142     if (sc->send) {
 143         return sc->send(dev, data);
 144     }
 145
 146     return -1;
 147 }
 148
 149 int i2c_recv(I2CBus *bus)
 150 {
 151     I2CSlave *dev = bus->current_dev;
 152     I2CSlaveClass *sc;
 153
 154     if (!dev) {
 155         return -1;
 156     }
 157
 158     sc = I2C_SLAVE_GET_CLASS(dev);
 159     if (sc->recv) {
 160         return sc->recv(dev);
 161     }
 162
 163     return -1;
 164 }
 165
 166 void i2c_nack(I2CBus *bus)
 167 {
 168     I2CSlave *dev = bus->current_dev;
 169     I2CSlaveClass *sc;
 170
 171     if (!dev) {
 172         return;
 173     }
 174
 175     sc = I2C_SLAVE_GET_CLASS(dev);
 176     if (sc->event) {
 177         sc->event(dev, I2C_NACK);
 178     }
 179 }
 180
 181 static int i2c_slave_post_load(void *opaque, int version_id)
 182 {
 183     I2CSlave *dev = opaque;
 184     I2CBus *bus;
 185     bus = I2C_BUS(qdev_get_parent_bus(DEVICE(dev)));
 186     if (bus->saved_address == dev->address) {
 187         bus->current_dev = dev;
 188     }
 189     return 0;
 190 }
 191
 192 const VMStateDescription vmstate_i2c_slave = {
 193     .name = "I2CSlave",
 194     .version_id = 1,
 195     .minimum_version_id = 1,
 196     .post_load = i2c_slave_post_load,
 197     .fields = (VMStateField[]) {
 198         VMSTATE_UINT8(address, I2CSlave),
 199         VMSTATE_END_OF_LIST()
 200     }
 201 };
 202
 203 static int i2c_slave_qdev_init(DeviceState *dev)
 204 {
 205     I2CSlave *s = I2C_SLAVE(dev);
 206     I2CSlaveClass *sc = I2C_SLAVE_GET_CLASS(s);
 207
 208     return sc->init(s);
 209 }
 210
 211 DeviceState *i2c_create_slave(I2CBus *bus, const char *name, uint8_t addr)
 212 {
 213     DeviceState *dev;
 214
 215     dev = qdev_create(&bus->qbus, name);
 216     qdev_prop_set_uint8(dev, "address", addr);
 217     qdev_init_nofail(dev);
 218     return dev;
 219 }
 220
 221 static void i2c_slave_class_init(ObjectClass *klass, void *data)
 222 {
 223     DeviceClass *k = DEVICE_CLASS(klass);
 224     k->init = i2c_slave_qdev_init;
 225     set_bit(DEVICE_CATEGORY_MISC, k->categories);
 226     k->bus_type = TYPE_I2C_BUS;
 227     k->props = i2c_props;
 228 }
 229
 230 static const TypeInfo i2c_slave_type_info = {
 231     .name = TYPE_I2C_SLAVE,
 232     .parent = TYPE_DEVICE,
 233     .instance_size = sizeof(I2CSlave),
 234     .abstract = true,
 235     .class_size = sizeof(I2CSlaveClass),
 236     .class_init = i2c_slave_class_init,
 237 };
 238
 239 static void i2c_slave_register_types(void)
 240 {
 241     type_register_static(&i2c_bus_info);
 242     type_register_static(&i2c_slave_type_info);
 243 }
 244
 245 type_init(i2c_slave_register_types)