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 struct I2CBus
  21 {
  22     BusState qbus;
  23     QLIST_HEAD(, I2CNode) current_devs;
  24     uint8_t saved_address;
  25     bool broadcast;
  26 };
  27
  28 static Property i2c_props[] = {
  29     DEFINE_PROP_UINT8("address", struct I2CSlave, address, 0),
  30     DEFINE_PROP_END_OF_LIST(),
  31 };
  32
  33 #define TYPE_I2C_BUS "i2c-bus"
  34 #define I2C_BUS(obj) OBJECT_CHECK(I2CBus, (obj), TYPE_I2C_BUS)
  35
  36 static const TypeInfo i2c_bus_info = {
  37     .name = TYPE_I2C_BUS,
  38     .parent = TYPE_BUS,
  39     .instance_size = sizeof(I2CBus),
  40 };
  41
  42 static void i2c_bus_pre_save(void *opaque)
  43 {
  44     I2CBus *bus = opaque;
  45
  46     bus->saved_address = -1;
  47     if (!QLIST_EMPTY(&bus->current_devs)) {
  48         if (!bus->broadcast) {
  49             bus->saved_address = QLIST_FIRST(&bus->current_devs)->elt->address;
  50         }
  51     }
  52 }
  53
  54 static const VMStateDescription vmstate_i2c_bus = {
  55     .name = "i2c_bus",
  56     .version_id = 1,
  57     .minimum_version_id = 1,
  58     .pre_save = i2c_bus_pre_save,
  59     .fields = (VMStateField[]) {
  60         VMSTATE_UINT8(saved_address, I2CBus),
  61         VMSTATE_BOOL(broadcast, I2CBus),
  62         VMSTATE_END_OF_LIST()
  63     }
  64 };
  65
  66 /* Create a new I2C bus.  */
  67 I2CBus *i2c_init_bus(DeviceState *parent, const char *name)
  68 {
  69     I2CBus *bus;
  70
  71     bus = I2C_BUS(qbus_create(TYPE_I2C_BUS, parent, name));
  72     QLIST_INIT(&bus->current_devs);
  73     vmstate_register(NULL, -1, &vmstate_i2c_bus, bus);
  74     return bus;
  75 }
  76
  77 void i2c_set_slave_address(I2CSlave *dev, uint8_t address)
  78 {
  79     dev->address = address;
  80 }
  81
  82 /* Return nonzero if bus is busy.  */
  83 int i2c_bus_busy(I2CBus *bus)
  84 {
  85     return !QLIST_EMPTY(&bus->current_devs);
  86 }
  87
  88 /* Returns non-zero if the address is not valid.  */
  89 /* TODO: Make this handle multiple masters.  */
  90 int i2c_start_transfer(I2CBus *bus, uint8_t address, int recv)
  91 {
  92     BusChild *kid;
  93     I2CSlaveClass *sc;
  94     I2CNode *node;
  95
  96     if (address == 0x00) {
  97         /*
  98          * This is a broadcast, the current_devs will be all the devices of the
  99          * bus.
 100          */
 101         bus->broadcast = true;
 102     }
 103
 104     QTAILQ_FOREACH(kid, &bus->qbus.children, sibling) {
 105         DeviceState *qdev = kid->child;
 106         I2CSlave *candidate = I2C_SLAVE(qdev);
 107         if ((candidate->address == address) || (bus->broadcast)) {
 108             node = g_malloc(sizeof(struct I2CNode));
 109             node->elt = candidate;
 110             QLIST_INSERT_HEAD(&bus->current_devs, node, next);
 111             if (!bus->broadcast) {
 112                 break;
 113             }
 114         }
 115     }
 116
 117     if (QLIST_EMPTY(&bus->current_devs)) {
 118         return 1;
 119     }
 120
 121     QLIST_FOREACH(node, &bus->current_devs, next) {
 122         sc = I2C_SLAVE_GET_CLASS(node->elt);
 123         /* If the bus is already busy, assume this is a repeated
 124            start condition.  */
 125         if (sc->event) {
 126             sc->event(node->elt, recv ? I2C_START_RECV : I2C_START_SEND);
 127         }
 128     }
 129     return 0;
 130 }
 131
 132 void i2c_end_transfer(I2CBus *bus)
 133 {
 134     I2CSlaveClass *sc;
 135     I2CNode *node, *next;
 136
 137     if (QLIST_EMPTY(&bus->current_devs)) {
 138         return;
 139     }
 140
 141     QLIST_FOREACH_SAFE(node, &bus->current_devs, next, next) {
 142         sc = I2C_SLAVE_GET_CLASS(node->elt);
 143         if (sc->event) {
 144             sc->event(node->elt, I2C_FINISH);
 145         }
 146         QLIST_REMOVE(node, next);
 147         g_free(node);
 148     }
 149     bus->broadcast = false;
 150 }
 151
 152 int i2c_send_recv(I2CBus *bus, uint8_t *data, bool send)
 153 {
 154     I2CSlaveClass *sc;
 155     I2CNode *node;
 156     int ret = 0;
 157
 158     if (send) {
 159         QLIST_FOREACH(node, &bus->current_devs, next) {
 160             sc = I2C_SLAVE_GET_CLASS(node->elt);
 161             if (sc->send) {
 162                 ret = ret || sc->send(node->elt, *data);
 163             } else {
 164                 ret = -1;
 165             }
 166         }
 167         return ret ? -1 : 0;
 168     } else {
 169         if ((QLIST_EMPTY(&bus->current_devs)) || (bus->broadcast)) {
 170             return -1;
 171         }
 172
 173         sc = I2C_SLAVE_GET_CLASS(QLIST_FIRST(&bus->current_devs)->elt);
 174         if (sc->recv) {
 175             ret = sc->recv(QLIST_FIRST(&bus->current_devs)->elt);
 176             if (ret < 0) {
 177                 return ret;
 178             } else {
 179                 *data = ret;
 180                 return 0;
 181             }
 182         }
 183         return -1;
 184     }
 185 }
 186
 187 int i2c_send(I2CBus *bus, uint8_t data)
 188 {
 189     return i2c_send_recv(bus, &data, true);
 190 }
 191
 192 int i2c_recv(I2CBus *bus)
 193 {
 194     uint8_t data;
 195     int ret = i2c_send_recv(bus, &data, false);
 196
 197     return ret < 0 ? ret : data;
 198 }
 199
 200 void i2c_nack(I2CBus *bus)
 201 {
 202     I2CSlaveClass *sc;
 203     I2CNode *node;
 204
 205     if (QLIST_EMPTY(&bus->current_devs)) {
 206         return;
 207     }
 208
 209     QLIST_FOREACH(node, &bus->current_devs, next) {
 210         sc = I2C_SLAVE_GET_CLASS(node->elt);
 211         if (sc->event) {
 212             sc->event(node->elt, I2C_NACK);
 213         }
 214     }
 215 }
 216
 217 static int i2c_slave_post_load(void *opaque, int version_id)
 218 {
 219     I2CSlave *dev = opaque;
 220     I2CBus *bus;
 221     I2CNode *node;
 222
 223     bus = I2C_BUS(qdev_get_parent_bus(DEVICE(dev)));
 224     if ((bus->saved_address == dev->address) || (bus->broadcast)) {
 225         node = g_malloc(sizeof(struct I2CNode));
 226         node->elt = dev;
 227         QLIST_INSERT_HEAD(&bus->current_devs, node, next);
 228     }
 229     return 0;
 230 }
 231
 232 const VMStateDescription vmstate_i2c_slave = {
 233     .name = "I2CSlave",
 234     .version_id = 1,
 235     .minimum_version_id = 1,
 236     .post_load = i2c_slave_post_load,
 237     .fields = (VMStateField[]) {
 238         VMSTATE_UINT8(address, I2CSlave),
 239         VMSTATE_END_OF_LIST()
 240     }
 241 };
 242
 243 static int i2c_slave_qdev_init(DeviceState *dev)
 244 {
 245     I2CSlave *s = I2C_SLAVE(dev);
 246     I2CSlaveClass *sc = I2C_SLAVE_GET_CLASS(s);
 247
 248     return sc->init(s);
 249 }
 250
 251 DeviceState *i2c_create_slave(I2CBus *bus, const char *name, uint8_t addr)
 252 {
 253     DeviceState *dev;
 254
 255     dev = qdev_create(&bus->qbus, name);
 256     qdev_prop_set_uint8(dev, "address", addr);
 257     qdev_init_nofail(dev);
 258     return dev;
 259 }
 260
 261 static void i2c_slave_class_init(ObjectClass *klass, void *data)
 262 {
 263     DeviceClass *k = DEVICE_CLASS(klass);
 264     k->init = i2c_slave_qdev_init;
 265     set_bit(DEVICE_CATEGORY_MISC, k->categories);
 266     k->bus_type = TYPE_I2C_BUS;
 267     k->props = i2c_props;
 268 }
 269
 270 static const TypeInfo i2c_slave_type_info = {
 271     .name = TYPE_I2C_SLAVE,
 272     .parent = TYPE_DEVICE,
 273     .instance_size = sizeof(I2CSlave),
 274     .abstract = true,
 275     .class_size = sizeof(I2CSlaveClass),
 276     .class_init = i2c_slave_class_init,
 277 };
 278
 279 static void i2c_slave_register_types(void)
 280 {
 281     type_register_static(&i2c_bus_info);
 282     type_register_static(&i2c_slave_type_info);
 283 }
 284
 285 type_init(i2c_slave_register_types)