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 "qemu/osdep.h"
  13 #include "hw/hw.h"
  14 #include "hw/i2c/i2c.h"
  15 #include "hw/i2c/smbus.h"
  16
  17 //#define DEBUG_SMBUS 1
  18
  19 #ifdef DEBUG_SMBUS
  20 #define DPRINTF(fmt, ...) \
  21 do { printf("smbus(%02x): " fmt , dev->i2c.address, ## __VA_ARGS__); } while (0)
  22 #define BADF(fmt, ...) \
  23 do { fprintf(stderr, "smbus: error: " fmt , ## __VA_ARGS__); exit(1);} while (0)
  24 #else
  25 #define DPRINTF(fmt, ...) do {} while(0)
  26 #define BADF(fmt, ...) \
  27 do { fprintf(stderr, "smbus: error: " fmt , ## __VA_ARGS__);} while (0)
  28 #endif
  29
  30 enum {
  31     SMBUS_IDLE,
  32     SMBUS_WRITE_DATA,
  33     SMBUS_RECV_BYTE,
  34     SMBUS_READ_DATA,
  35     SMBUS_DONE,
  36     SMBUS_CONFUSED = -1
  37 };
  38
  39 static void smbus_do_quick_cmd(SMBusDevice *dev, int recv)
  40 {
  41     SMBusDeviceClass *sc = SMBUS_DEVICE_GET_CLASS(dev);
  42
  43     DPRINTF("Quick Command %d\n", recv);
  44     if (sc->quick_cmd) {
  45         sc->quick_cmd(dev, recv);
  46     }
  47 }
  48
  49 static void smbus_do_write(SMBusDevice *dev)
  50 {
  51     SMBusDeviceClass *sc = SMBUS_DEVICE_GET_CLASS(dev);
  52
  53     if (dev->data_len == 0) {
  54         smbus_do_quick_cmd(dev, 0);
  55     } else if (dev->data_len == 1) {
  56         DPRINTF("Send Byte\n");
  57         if (sc->send_byte) {
  58             sc->send_byte(dev, dev->data_buf[0]);
  59         }
  60     } else {
  61         dev->command = dev->data_buf[0];
  62         DPRINTF("Command %d len %d\n", dev->command, dev->data_len - 1);
  63         if (sc->write_data) {
  64             sc->write_data(dev, dev->command, dev->data_buf + 1,
  65                            dev->data_len - 1);
  66         }
  67     }
  68 }
  69
  70 static int smbus_i2c_event(I2CSlave *s, enum i2c_event event)
  71 {
  72     SMBusDevice *dev = SMBUS_DEVICE(s);
  73
  74     switch (event) {
  75     case I2C_START_SEND:
  76         switch (dev->mode) {
  77         case SMBUS_IDLE:
  78             DPRINTF("Incoming data\n");
  79             dev->mode = SMBUS_WRITE_DATA;
  80             break;
  81         default:
  82             BADF("Unexpected send start condition in state %d\n", dev->mode);
  83             dev->mode = SMBUS_CONFUSED;
  84             break;
  85         }
  86         break;
  87
  88     case I2C_START_RECV:
  89         switch (dev->mode) {
  90         case SMBUS_IDLE:
  91             DPRINTF("Read mode\n");
  92             dev->mode = SMBUS_RECV_BYTE;
  93             break;
  94         case SMBUS_WRITE_DATA:
  95             if (dev->data_len == 0) {
  96                 BADF("Read after write with no data\n");
  97                 dev->mode = SMBUS_CONFUSED;
  98             } else {
  99                 if (dev->data_len > 1) {
 100                     smbus_do_write(dev);
 101                 } else {
 102                     dev->command = dev->data_buf[0];
 103                     DPRINTF("%02x: Command %d\n", dev->i2c.address,
 104                             dev->command);
 105                 }
 106                 DPRINTF("Read mode\n");
 107                 dev->data_len = 0;
 108                 dev->mode = SMBUS_READ_DATA;
 109             }
 110             break;
 111         default:
 112             BADF("Unexpected recv start condition in state %d\n", dev->mode);
 113             dev->mode = SMBUS_CONFUSED;
 114             break;
 115         }
 116         break;
 117
 118     case I2C_FINISH:
 119         switch (dev->mode) {
 120         case SMBUS_WRITE_DATA:
 121             smbus_do_write(dev);
 122             break;
 123         case SMBUS_RECV_BYTE:
 124             smbus_do_quick_cmd(dev, 1);
 125             break;
 126         case SMBUS_READ_DATA:
 127             BADF("Unexpected stop during receive\n");
 128             break;
 129         default:
 130             /* Nothing to do.  */
 131             break;
 132         }
 133         dev->mode = SMBUS_IDLE;
 134         dev->data_len = 0;
 135         break;
 136
 137     case I2C_NACK:
 138         switch (dev->mode) {
 139         case SMBUS_DONE:
 140             /* Nothing to do.  */
 141             break;
 142         case SMBUS_READ_DATA:
 143             dev->mode = SMBUS_DONE;
 144             break;
 145         default:
 146             BADF("Unexpected NACK in state %d\n", dev->mode);
 147             dev->mode = SMBUS_CONFUSED;
 148             break;
 149         }
 150     }
 151
 152     return 0;
 153 }
 154
 155 static int smbus_i2c_recv(I2CSlave *s)
 156 {
 157     SMBusDevice *dev = SMBUS_DEVICE(s);
 158     SMBusDeviceClass *sc = SMBUS_DEVICE_GET_CLASS(dev);
 159     int ret;
 160
 161     switch (dev->mode) {
 162     case SMBUS_RECV_BYTE:
 163         if (sc->receive_byte) {
 164             ret = sc->receive_byte(dev);
 165         } else {
 166             ret = 0;
 167         }
 168         DPRINTF("Receive Byte %02x\n", ret);
 169         dev->mode = SMBUS_DONE;
 170         break;
 171     case SMBUS_READ_DATA:
 172         if (sc->read_data) {
 173             ret = sc->read_data(dev, dev->command, dev->data_len);
 174             dev->data_len++;
 175         } else {
 176             ret = 0;
 177         }
 178         DPRINTF("Read data %02x\n", ret);
 179         break;
 180     default:
 181         BADF("Unexpected read in state %d\n", dev->mode);
 182         dev->mode = SMBUS_CONFUSED;
 183         ret = 0;
 184         break;
 185     }
 186     return ret;
 187 }
 188
 189 static int smbus_i2c_send(I2CSlave *s, uint8_t data)
 190 {
 191     SMBusDevice *dev = SMBUS_DEVICE(s);
 192
 193     switch (dev->mode) {
 194     case SMBUS_WRITE_DATA:
 195         DPRINTF("Write data %02x\n", data);
 196         dev->data_buf[dev->data_len++] = data;
 197         break;
 198     default:
 199         BADF("Unexpected write in state %d\n", dev->mode);
 200         break;
 201     }
 202     return 0;
 203 }
 204
 205 static int smbus_device_init(I2CSlave *i2c)
 206 {
 207     SMBusDevice *dev = SMBUS_DEVICE(i2c);
 208     SMBusDeviceClass *sc = SMBUS_DEVICE_GET_CLASS(dev);
 209
 210     return sc->init(dev);
 211 }
 212
 213 /* Master device commands.  */
 214 int smbus_quick_command(I2CBus *bus, uint8_t addr, int read)
 215 {
 216     if (i2c_start_transfer(bus, addr, read)) {
 217         return -1;
 218     }
 219     i2c_end_transfer(bus);
 220     return 0;
 221 }
 222
 223 int smbus_receive_byte(I2CBus *bus, uint8_t addr)
 224 {
 225     uint8_t data;
 226
 227     if (i2c_start_transfer(bus, addr, 1)) {
 228         return -1;
 229     }
 230     data = i2c_recv(bus);
 231     i2c_nack(bus);
 232     i2c_end_transfer(bus);
 233     return data;
 234 }
 235
 236 int smbus_send_byte(I2CBus *bus, uint8_t addr, uint8_t data)
 237 {
 238     if (i2c_start_transfer(bus, addr, 0)) {
 239         return -1;
 240     }
 241     i2c_send(bus, data);
 242     i2c_end_transfer(bus);
 243     return 0;
 244 }
 245
 246 int smbus_read_byte(I2CBus *bus, uint8_t addr, uint8_t command)
 247 {
 248     uint8_t data;
 249     if (i2c_start_transfer(bus, addr, 0)) {
 250         return -1;
 251     }
 252     i2c_send(bus, command);
 253     if (i2c_start_transfer(bus, addr, 1)) {
 254         i2c_end_transfer(bus);
 255         return -1;
 256     }
 257     data = i2c_recv(bus);
 258     i2c_nack(bus);
 259     i2c_end_transfer(bus);
 260     return data;
 261 }
 262
 263 int smbus_write_byte(I2CBus *bus, uint8_t addr, uint8_t command, uint8_t data)
 264 {
 265     if (i2c_start_transfer(bus, addr, 0)) {
 266         return -1;
 267     }
 268     i2c_send(bus, command);
 269     i2c_send(bus, data);
 270     i2c_end_transfer(bus);
 271     return 0;
 272 }
 273
 274 int smbus_read_word(I2CBus *bus, uint8_t addr, uint8_t command)
 275 {
 276     uint16_t data;
 277     if (i2c_start_transfer(bus, addr, 0)) {
 278         return -1;
 279     }
 280     i2c_send(bus, command);
 281     if (i2c_start_transfer(bus, addr, 1)) {
 282         i2c_end_transfer(bus);
 283         return -1;
 284     }
 285     data = i2c_recv(bus);
 286     data |= i2c_recv(bus) << 8;
 287     i2c_nack(bus);
 288     i2c_end_transfer(bus);
 289     return data;
 290 }
 291
 292 int smbus_write_word(I2CBus *bus, uint8_t addr, uint8_t command, uint16_t data)
 293 {
 294     if (i2c_start_transfer(bus, addr, 0)) {
 295         return -1;
 296     }
 297     i2c_send(bus, command);
 298     i2c_send(bus, data & 0xff);
 299     i2c_send(bus, data >> 8);
 300     i2c_end_transfer(bus);
 301     return 0;
 302 }
 303
 304 int smbus_read_block(I2CBus *bus, uint8_t addr, uint8_t command, uint8_t *data)
 305 {
 306     int len;
 307     int i;
 308
 309     if (i2c_start_transfer(bus, addr, 0)) {
 310         return -1;
 311     }
 312     i2c_send(bus, command);
 313     if (i2c_start_transfer(bus, addr, 1)) {
 314         i2c_end_transfer(bus);
 315         return -1;
 316     }
 317     len = i2c_recv(bus);
 318     if (len > 32) {
 319         len = 0;
 320     }
 321     for (i = 0; i < len; i++) {
 322         data[i] = i2c_recv(bus);
 323     }
 324     i2c_nack(bus);
 325     i2c_end_transfer(bus);
 326     return len;
 327 }
 328
 329 int smbus_write_block(I2CBus *bus, uint8_t addr, uint8_t command, uint8_t *data,
 330                       int len)
 331 {
 332     int i;
 333
 334     if (len > 32)
 335         len = 32;
 336
 337     if (i2c_start_transfer(bus, addr, 0)) {
 338         return -1;
 339     }
 340     i2c_send(bus, command);
 341     i2c_send(bus, len);
 342     for (i = 0; i < len; i++) {
 343         i2c_send(bus, data[i]);
 344     }
 345     i2c_end_transfer(bus);
 346     return 0;
 347 }
 348
 349 static void smbus_device_class_init(ObjectClass *klass, void *data)
 350 {
 351     I2CSlaveClass *sc = I2C_SLAVE_CLASS(klass);
 352
 353     sc->init = smbus_device_init;
 354     sc->event = smbus_i2c_event;
 355     sc->recv = smbus_i2c_recv;
 356     sc->send = smbus_i2c_send;
 357 }
 358
 359 static const TypeInfo smbus_device_type_info = {
 360     .name = TYPE_SMBUS_DEVICE,
 361     .parent = TYPE_I2C_SLAVE,
 362     .instance_size = sizeof(SMBusDevice),
 363     .abstract = true,
 364     .class_size = sizeof(SMBusDeviceClass),
 365     .class_init = smbus_device_class_init,
 366 };
 367
 368 static void smbus_device_register_types(void)
 369 {
 370     type_register_static(&smbus_device_type_info);
 371 }
 372
 373 type_init(smbus_device_register_types)