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 "qemu/osdep.h"
  11 #include "hw/i2c/i2c.h"
  12
  13 typedef struct I2CNode I2CNode;
  14
  15 struct I2CNode {
  16     I2CSlave *elt;
  17     QLIST_ENTRY(I2CNode) next;
  18 };
  19
  20 #define I2C_BROADCAST 0x00
  21
  22 struct I2CBus
  23 {
  24     BusState qbus;
  25     QLIST_HEAD(, I2CNode) current_devs;
  26     uint8_t saved_address;
  27     bool broadcast;
  28 };
  29
  30 static Property i2c_props[] = {
  31     DEFINE_PROP_UINT8("address", struct I2CSlave, address, 0),
  32     DEFINE_PROP_END_OF_LIST(),
  33 };
  34
  35 #define TYPE_I2C_BUS "i2c-bus"
  36 #define I2C_BUS(obj) OBJECT_CHECK(I2CBus, (obj), TYPE_I2C_BUS)
  37
  38 static const TypeInfo i2c_bus_info = {
  39     .name = TYPE_I2C_BUS,
  40     .parent = TYPE_BUS,
  41     .instance_size = sizeof(I2CBus),
  42 };
  43
  44 static void i2c_bus_pre_save(void *opaque)
  45 {
  46     I2CBus *bus = opaque;
  47
  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;
  54         }
  55     }
  56 }
  57
  58 static const VMStateDescription vmstate_i2c_bus = {
  59     .name = "i2c_bus",
  60     .version_id = 1,
  61     .minimum_version_id = 1,
  62     .pre_save = i2c_bus_pre_save,
  63     .fields = (VMStateField[]) {
  64         VMSTATE_UINT8(saved_address, I2CBus),
  65         VMSTATE_END_OF_LIST()
  66     }
  67 };
  68
  69 /* Create a new I2C bus.  */
  70 I2CBus *i2c_init_bus(DeviceState *parent, const char *name)
  71 {
  72     I2CBus *bus;
  73
  74     bus = I2C_BUS(qbus_create(TYPE_I2C_BUS, parent, name));
  75     QLIST_INIT(&bus->current_devs);
  76     vmstate_register(NULL, -1, &vmstate_i2c_bus, bus);
  77     return bus;
  78 }
  79
  80 void i2c_set_slave_address(I2CSlave *dev, uint8_t address)
  81 {
  82     dev->address = address;
  83 }
  84
  85 /* Return nonzero if bus is busy.  */
  86 int i2c_bus_busy(I2CBus *bus)
  87 {
  88     return !QLIST_EMPTY(&bus->current_devs);
  89 }
  90
  91 /* Returns non-zero if the address is not valid.  */
  92 /* TODO: Make this handle multiple masters.  */
  93 int i2c_start_transfer(I2CBus *bus, uint8_t address, int recv)
  94 {
  95     BusChild *kid;
  96     I2CSlaveClass *sc;
  97     I2CNode *node;
  98
  99     if (address == I2C_BROADCAST) {
 100         /*
 101          * This is a broadcast, the current_devs will be all the devices of the
 102          * bus.
 103          */
 104         bus->broadcast = true;
 105     }
 106
 107     QTAILQ_FOREACH(kid, &bus->qbus.children, sibling) {
 108         DeviceState *qdev = kid->child;
 109         I2CSlave *candidate = I2C_SLAVE(qdev);
 110         if ((candidate->address == address) || (bus->broadcast)) {
 111             node = g_malloc(sizeof(struct I2CNode));
 112             node->elt = candidate;
 113             QLIST_INSERT_HEAD(&bus->current_devs, node, next);
 114             if (!bus->broadcast) {
 115                 break;
 116             }
 117         }
 118     }
 119
 120     if (QLIST_EMPTY(&bus->current_devs)) {
 121         return 1;
 122     }
 123
 124     QLIST_FOREACH(node, &bus->current_devs, next) {
 125         sc = I2C_SLAVE_GET_CLASS(node->elt);
 126         /* If the bus is already busy, assume this is a repeated
 127            start condition.  */
 128         if (sc->event) {
 129             sc->event(node->elt, recv ? I2C_START_RECV : I2C_START_SEND);
 130         }
 131     }
 132     return 0;
 133 }
 134
 135 void i2c_end_transfer(I2CBus *bus)
 136 {
 137     I2CSlaveClass *sc;
 138     I2CNode *node, *next;
 139
 140     if (QLIST_EMPTY(&bus->current_devs)) {
 141         return;
 142     }
 143
 144     QLIST_FOREACH_SAFE(node, &bus->current_devs, next, next) {
 145         sc = I2C_SLAVE_GET_CLASS(node->elt);
 146         if (sc->event) {
 147             sc->event(node->elt, I2C_FINISH);
 148         }
 149         QLIST_REMOVE(node, next);
 150         g_free(node);
 151     }
 152     bus->broadcast = false;
 153 }
 154
 155 int i2c_send_recv(I2CBus *bus, uint8_t *data, bool send)
 156 {
 157     I2CSlaveClass *sc;
 158     I2CNode *node;
 159     int ret = 0;
 160
 161     if (send) {
 162         QLIST_FOREACH(node, &bus->current_devs, next) {
 163             sc = I2C_SLAVE_GET_CLASS(node->elt);
 164             if (sc->send) {
 165                 ret = ret || sc->send(node->elt, *data);
 166             } else {
 167                 ret = -1;
 168             }
 169         }
 170         return ret ? -1 : 0;
 171     } else {
 172         if ((QLIST_EMPTY(&bus->current_devs)) || (bus->broadcast)) {
 173             return -1;
 174         }
 175
 176         sc = I2C_SLAVE_GET_CLASS(QLIST_FIRST(&bus->current_devs)->elt);
 177         if (sc->recv) {
 178             ret = sc->recv(QLIST_FIRST(&bus->current_devs)->elt);
 179             if (ret < 0) {
 180                 return ret;
 181             } else {
 182                 *data = ret;
 183                 return 0;
 184             }
 185         }
 186         return -1;
 187     }
 188 }
 189
 190 int i2c_send(I2CBus *bus, uint8_t data)
 191 {
 192     return i2c_send_recv(bus, &data, true);
 193 }
 194
 195 int i2c_recv(I2CBus *bus)
 196 {
 197     uint8_t data;
 198     int ret = i2c_send_recv(bus, &data, false);
 199
 200     return ret < 0 ? ret : data;
 201 }
 202
 203 void i2c_nack(I2CBus *bus)
 204 {
 205     I2CSlaveClass *sc;
 206     I2CNode *node;
 207
 208     if (QLIST_EMPTY(&bus->current_devs)) {
 209         return;
 210     }
 211
 212     QLIST_FOREACH(node, &bus->current_devs, next) {
 213         sc = I2C_SLAVE_GET_CLASS(node->elt);
 214         if (sc->event) {
 215             sc->event(node->elt, I2C_NACK);
 216         }
 217     }
 218 }
 219
 220 static int i2c_slave_post_load(void *opaque, int version_id)
 221 {
 222     I2CSlave *dev = opaque;
 223     I2CBus *bus;
 224     I2CNode *node;
 225
 226     bus = I2C_BUS(qdev_get_parent_bus(DEVICE(dev)));
 227     if ((bus->saved_address == dev->address) ||
 228         (bus->saved_address == I2C_BROADCAST)) {
 229         node = g_malloc(sizeof(struct I2CNode));
 230         node->elt = dev;
 231         QLIST_INSERT_HEAD(&bus->current_devs, node, next);
 232     }
 233     return 0;
 234 }
 235
 236 const VMStateDescription vmstate_i2c_slave = {
 237     .name = "I2CSlave",
 238     .version_id = 1,
 239     .minimum_version_id = 1,
 240     .post_load = i2c_slave_post_load,
 241     .fields = (VMStateField[]) {
 242         VMSTATE_UINT8(address, I2CSlave),
 243         VMSTATE_END_OF_LIST()
 244     }
 245 };
 246
 247 static int i2c_slave_qdev_init(DeviceState *dev)
 248 {
 249     I2CSlave *s = I2C_SLAVE(dev);
 250     I2CSlaveClass *sc = I2C_SLAVE_GET_CLASS(s);
 251
 252     return sc->init(s);
 253 }
 254
 255 DeviceState *i2c_create_slave(I2CBus *bus, const char *name, uint8_t addr)
 256 {
 257     DeviceState *dev;
 258
 259     dev = qdev_create(&bus->qbus, name);
 260     qdev_prop_set_uint8(dev, "address", addr);
 261     qdev_init_nofail(dev);
 262     return dev;
 263 }
 264
 265 static void i2c_slave_class_init(ObjectClass *klass, void *data)
 266 {
 267     DeviceClass *k = DEVICE_CLASS(klass);
 268     k->init = i2c_slave_qdev_init;
 269     set_bit(DEVICE_CATEGORY_MISC, k->categories);
 270     k->bus_type = TYPE_I2C_BUS;
 271     k->props = i2c_props;
 272 }
 273
 274 static const TypeInfo i2c_slave_type_info = {
 275     .name = TYPE_I2C_SLAVE,
 276     .parent = TYPE_DEVICE,
 277     .instance_size = sizeof(I2CSlave),
 278     .abstract = true,
 279     .class_size = sizeof(I2CSlaveClass),
 280     .class_init = i2c_slave_class_init,
 281 };
 282
 283 static void i2c_slave_register_types(void)
 284 {
 285     type_register_static(&i2c_bus_info);
 286     type_register_static(&i2c_slave_type_info);
 287 }
 288
 289 type_init(i2c_slave_register_types)