hw/i2c/smbus.c

   1 /*
   2  * QEMU SMBus device emulation.
   3  *
   4  * Copyright (c) 2007 CodeSourcery.
   5  * Written by Paul Brook
   6  *
   7  * This code is licensed under the LGPL.
   8  */
   9
  10 /* TODO: Implement PEC.  */
  11
  12 #include "hw/hw.h"
  13 #include "hw/i2c/i2c.h"
  14 #include "hw/i2c/smbus.h"
  15
  16 //#define DEBUG_SMBUS 1
  17
  18 #ifdef DEBUG_SMBUS
  19 #define DPRINTF(fmt, ...) \
  20 do { printf("smbus(%02x): " fmt , dev->i2c.address, ## __VA_ARGS__); } while (0)
  21 #define BADF(fmt, ...) \
  22 do { fprintf(stderr, "smbus: error: " fmt , ## __VA_ARGS__); exit(1);} while (0)
  23 #else
  24 #define DPRINTF(fmt, ...) do {} while(0)
  25 #define BADF(fmt, ...) \
  26 do { fprintf(stderr, "smbus: error: " fmt , ## __VA_ARGS__);} while (0)
  27 #endif
  28
  29 enum {
  30     SMBUS_IDLE,
  31     SMBUS_WRITE_DATA,
  32     SMBUS_RECV_BYTE,
  33     SMBUS_READ_DATA,
  34     SMBUS_DONE,
  35     SMBUS_CONFUSED = -1
  36 };
  37
  38 static void smbus_do_quick_cmd(SMBusDevice *dev, int recv)
  39 {
  40     SMBusDeviceClass *sc = SMBUS_DEVICE_GET_CLASS(dev);
  41
  42     DPRINTF("Quick Command %d\n", recv);
  43     if (sc->quick_cmd) {
  44         sc->quick_cmd(dev, recv);
  45     }
  46 }
  47
  48 static void smbus_do_write(SMBusDevice *dev)
  49 {
  50     SMBusDeviceClass *sc = SMBUS_DEVICE_GET_CLASS(dev);
  51
  52     if (dev->data_len == 0) {
  53         smbus_do_quick_cmd(dev, 0);
  54     } else if (dev->data_len == 1) {
  55         DPRINTF("Send Byte\n");
  56         if (sc->send_byte) {
  57             sc->send_byte(dev, dev->data_buf[0]);
  58         }
  59     } else {
  60         dev->command = dev->data_buf[0];
  61         DPRINTF("Command %d len %d\n", dev->command, dev->data_len - 1);
  62         if (sc->write_data) {
  63             sc->write_data(dev, dev->command, dev->data_buf + 1,
  64                            dev->data_len - 1);
  65         }
  66     }
  67 }
  68
  69 static void smbus_i2c_event(I2CSlave *s, enum i2c_event event)
  70 {
  71     SMBusDevice *dev = SMBUS_DEVICE(s);
  72
  73     switch (event) {
  74     case I2C_START_SEND:
  75         switch (dev->mode) {
  76         case SMBUS_IDLE:
  77             DPRINTF("Incoming data\n");
  78             dev->mode = SMBUS_WRITE_DATA;
  79             break;
  80         default:
  81             BADF("Unexpected send start condition in state %d\n", dev->mode);
  82             dev->mode = SMBUS_CONFUSED;
  83             break;
  84         }
  85         break;
  86
  87     case I2C_START_RECV:
  88         switch (dev->mode) {
  89         case SMBUS_IDLE:
  90             DPRINTF("Read mode\n");
  91             dev->mode = SMBUS_RECV_BYTE;
  92             break;
  93         case SMBUS_WRITE_DATA:
  94             if (dev->data_len == 0) {
  95                 BADF("Read after write with no data\n");
  96                 dev->mode = SMBUS_CONFUSED;
  97             } else {
  98                 if (dev->data_len > 1) {
  99                     smbus_do_write(dev);
 100                 } else {
 101                     dev->command = dev->data_buf[0];
 102                     DPRINTF("%02x: Command %d\n", dev->i2c.address,
 103                             dev->command);
 104                 }
 105                 DPRINTF("Read mode\n");
 106                 dev->data_len = 0;
 107                 dev->mode = SMBUS_READ_DATA;
 108             }
 109             break;
 110         default:
 111             BADF("Unexpected recv start condition in state %d\n", dev->mode);
 112             dev->mode = SMBUS_CONFUSED;
 113             break;
 114         }
 115         break;
 116
 117     case I2C_FINISH:
 118         switch (dev->mode) {
 119         case SMBUS_WRITE_DATA:
 120             smbus_do_write(dev);
 121             break;
 122         case SMBUS_RECV_BYTE:
 123             smbus_do_quick_cmd(dev, 1);
 124             break;
 125         case SMBUS_READ_DATA:
 126             BADF("Unexpected stop during receive\n");
 127             break;
 128         default:
 129             /* Nothing to do.  */
 130             break;
 131         }
 132         dev->mode = SMBUS_IDLE;
 133         dev->data_len = 0;
 134         break;
 135
 136     case I2C_NACK:
 137         switch (dev->mode) {
 138         case SMBUS_DONE:
 139             /* Nothing to do.  */
 140             break;
 141         case SMBUS_READ_DATA:
 142             dev->mode = SMBUS_DONE;
 143             break;
 144         default:
 145             BADF("Unexpected NACK in state %d\n", dev->mode);
 146             dev->mode = SMBUS_CONFUSED;
 147             break;
 148         }
 149     }
 150 }
 151
 152 static int smbus_i2c_recv(I2CSlave *s)
 153 {
 154     SMBusDevice *dev = SMBUS_DEVICE(s);
 155     SMBusDeviceClass *sc = SMBUS_DEVICE_GET_CLASS(dev);
 156     int ret;
 157
 158     switch (dev->mode) {
 159     case SMBUS_RECV_BYTE:
 160         if (sc->receive_byte) {
 161             ret = sc->receive_byte(dev);
 162         } else {
 163             ret = 0;
 164         }
 165         DPRINTF("Receive Byte %02x\n", ret);
 166         dev->mode = SMBUS_DONE;
 167         break;
 168     case SMBUS_READ_DATA:
 169         if (sc->read_data) {
 170             ret = sc->read_data(dev, dev->command, dev->data_len);
 171             dev->data_len++;
 172         } else {
 173             ret = 0;
 174         }
 175         DPRINTF("Read data %02x\n", ret);
 176         break;
 177     default:
 178         BADF("Unexpected read in state %d\n", dev->mode);
 179         dev->mode = SMBUS_CONFUSED;
 180         ret = 0;
 181         break;
 182     }
 183     return ret;
 184 }
 185
 186 static int smbus_i2c_send(I2CSlave *s, uint8_t data)
 187 {
 188     SMBusDevice *dev = SMBUS_DEVICE(s);
 189
 190     switch (dev->mode) {
 191     case SMBUS_WRITE_DATA:
 192         DPRINTF("Write data %02x\n", data);
 193         dev->data_buf[dev->data_len++] = data;
 194         break;
 195     default:
 196         BADF("Unexpected write in state %d\n", dev->mode);
 197         break;
 198     }
 199     return 0;
 200 }
 201
 202 static int smbus_device_init(I2CSlave *i2c)
 203 {
 204     SMBusDevice *dev = SMBUS_DEVICE(i2c);
 205     SMBusDeviceClass *sc = SMBUS_DEVICE_GET_CLASS(dev);
 206
 207     return sc->init(dev);
 208 }
 209
 210 /* Master device commands.  */
 211 void smbus_quick_command(i2c_bus *bus, uint8_t addr, int read)
 212 {
 213     i2c_start_transfer(bus, addr, read);
 214     i2c_end_transfer(bus);
 215 }
 216
 217 uint8_t smbus_receive_byte(i2c_bus *bus, uint8_t addr)
 218 {
 219     uint8_t data;
 220
 221     i2c_start_transfer(bus, addr, 1);
 222     data = i2c_recv(bus);
 223     i2c_nack(bus);
 224     i2c_end_transfer(bus);
 225     return data;
 226 }
 227
 228 void smbus_send_byte(i2c_bus *bus, uint8_t addr, uint8_t data)
 229 {
 230     i2c_start_transfer(bus, addr, 0);
 231     i2c_send(bus, data);
 232     i2c_end_transfer(bus);
 233 }
 234
 235 uint8_t smbus_read_byte(i2c_bus *bus, uint8_t addr, uint8_t command)
 236 {
 237     uint8_t data;
 238     i2c_start_transfer(bus, addr, 0);
 239     i2c_send(bus, command);
 240     i2c_start_transfer(bus, addr, 1);
 241     data = i2c_recv(bus);
 242     i2c_nack(bus);
 243     i2c_end_transfer(bus);
 244     return data;
 245 }
 246
 247 void smbus_write_byte(i2c_bus *bus, uint8_t addr, uint8_t command, uint8_t data)
 248 {
 249     i2c_start_transfer(bus, addr, 0);
 250     i2c_send(bus, command);
 251     i2c_send(bus, data);
 252     i2c_end_transfer(bus);
 253 }
 254
 255 uint16_t smbus_read_word(i2c_bus *bus, uint8_t addr, uint8_t command)
 256 {
 257     uint16_t data;
 258     i2c_start_transfer(bus, addr, 0);
 259     i2c_send(bus, command);
 260     i2c_start_transfer(bus, addr, 1);
 261     data = i2c_recv(bus);
 262     data |= i2c_recv(bus) << 8;
 263     i2c_nack(bus);
 264     i2c_end_transfer(bus);
 265     return data;
 266 }
 267
 268 void smbus_write_word(i2c_bus *bus, uint8_t addr, uint8_t command, uint16_t data)
 269 {
 270     i2c_start_transfer(bus, addr, 0);
 271     i2c_send(bus, command);
 272     i2c_send(bus, data & 0xff);
 273     i2c_send(bus, data >> 8);
 274     i2c_end_transfer(bus);
 275 }
 276
 277 int smbus_read_block(i2c_bus *bus, uint8_t addr, uint8_t command, uint8_t *data)
 278 {
 279     int len;
 280     int i;
 281
 282     i2c_start_transfer(bus, addr, 0);
 283     i2c_send(bus, command);
 284     i2c_start_transfer(bus, addr, 1);
 285     len = i2c_recv(bus);
 286     if (len > 32)
 287         len = 0;
 288     for (i = 0; i < len; i++)
 289         data[i] = i2c_recv(bus);
 290     i2c_nack(bus);
 291     i2c_end_transfer(bus);
 292     return len;
 293 }
 294
 295 void smbus_write_block(i2c_bus *bus, uint8_t addr, uint8_t command, uint8_t *data,
 296                        int len)
 297 {
 298     int i;
 299
 300     if (len > 32)
 301         len = 32;
 302
 303     i2c_start_transfer(bus, addr, 0);
 304     i2c_send(bus, command);
 305     i2c_send(bus, len);
 306     for (i = 0; i < len; i++)
 307         i2c_send(bus, data[i]);
 308     i2c_end_transfer(bus);
 309 }
 310
 311 static void smbus_device_class_init(ObjectClass *klass, void *data)
 312 {
 313     I2CSlaveClass *sc = I2C_SLAVE_CLASS(klass);
 314
 315     sc->init = smbus_device_init;
 316     sc->event = smbus_i2c_event;
 317     sc->recv = smbus_i2c_recv;
 318     sc->send = smbus_i2c_send;
 319 }
 320
 321 static const TypeInfo smbus_device_type_info = {
 322     .name = TYPE_SMBUS_DEVICE,
 323     .parent = TYPE_I2C_SLAVE,
 324     .instance_size = sizeof(SMBusDevice),
 325     .abstract = true,
 326     .class_size = sizeof(SMBusDeviceClass),
 327     .class_init = smbus_device_class_init,
 328 };
 329
 330 static void smbus_device_register_types(void)
 331 {
 332     type_register_static(&smbus_device_type_info);
 333 }
 334
 335 type_init(smbus_device_register_types)