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 void 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
 153 static int smbus_i2c_recv(I2CSlave *s)
 154 {
 155     SMBusDevice *dev = SMBUS_DEVICE(s);
 156     SMBusDeviceClass *sc = SMBUS_DEVICE_GET_CLASS(dev);
 157     int ret;
 158
 159     switch (dev->mode) {
 160     case SMBUS_RECV_BYTE:
 161         if (sc->receive_byte) {
 162             ret = sc->receive_byte(dev);
 163         } else {
 164             ret = 0;
 165         }
 166         DPRINTF("Receive Byte %02x\n", ret);
 167         dev->mode = SMBUS_DONE;
 168         break;
 169     case SMBUS_READ_DATA:
 170         if (sc->read_data) {
 171             ret = sc->read_data(dev, dev->command, dev->data_len);
 172             dev->data_len++;
 173         } else {
 174             ret = 0;
 175         }
 176         DPRINTF("Read data %02x\n", ret);
 177         break;
 178     default:
 179         BADF("Unexpected read in state %d\n", dev->mode);
 180         dev->mode = SMBUS_CONFUSED;
 181         ret = 0;
 182         break;
 183     }
 184     return ret;
 185 }
 186
 187 static int smbus_i2c_send(I2CSlave *s, uint8_t data)
 188 {
 189     SMBusDevice *dev = SMBUS_DEVICE(s);
 190
 191     switch (dev->mode) {
 192     case SMBUS_WRITE_DATA:
 193         DPRINTF("Write data %02x\n", data);
 194         dev->data_buf[dev->data_len++] = data;
 195         break;
 196     default:
 197         BADF("Unexpected write in state %d\n", dev->mode);
 198         break;
 199     }
 200     return 0;
 201 }
 202
 203 static int smbus_device_init(I2CSlave *i2c)
 204 {
 205     SMBusDevice *dev = SMBUS_DEVICE(i2c);
 206     SMBusDeviceClass *sc = SMBUS_DEVICE_GET_CLASS(dev);
 207
 208     return sc->init(dev);
 209 }
 210
 211 /* Master device commands.  */
 212 int smbus_quick_command(I2CBus *bus, uint8_t addr, int read)
 213 {
 214     if (i2c_start_transfer(bus, addr, read)) {
 215         return -1;
 216     }
 217     i2c_end_transfer(bus);
 218     return 0;
 219 }
 220
 221 int smbus_receive_byte(I2CBus *bus, uint8_t addr)
 222 {
 223     uint8_t data;
 224
 225     if (i2c_start_transfer(bus, addr, 1)) {
 226         return -1;
 227     }
 228     data = i2c_recv(bus);
 229     i2c_nack(bus);
 230     i2c_end_transfer(bus);
 231     return data;
 232 }
 233
 234 int smbus_send_byte(I2CBus *bus, uint8_t addr, uint8_t data)
 235 {
 236     if (i2c_start_transfer(bus, addr, 0)) {
 237         return -1;
 238     }
 239     i2c_send(bus, data);
 240     i2c_end_transfer(bus);
 241     return 0;
 242 }
 243
 244 int smbus_read_byte(I2CBus *bus, uint8_t addr, uint8_t command)
 245 {
 246     uint8_t data;
 247     if (i2c_start_transfer(bus, addr, 0)) {
 248         return -1;
 249     }
 250     i2c_send(bus, command);
 251     if (i2c_start_transfer(bus, addr, 1)) {
 252         assert(0);
 253     }
 254     data = i2c_recv(bus);
 255     i2c_nack(bus);
 256     i2c_end_transfer(bus);
 257     return data;
 258 }
 259
 260 int smbus_write_byte(I2CBus *bus, uint8_t addr, uint8_t command, uint8_t data)
 261 {
 262     if (i2c_start_transfer(bus, addr, 0)) {
 263         return -1;
 264     }
 265     i2c_send(bus, command);
 266     i2c_send(bus, data);
 267     i2c_end_transfer(bus);
 268     return 0;
 269 }
 270
 271 int smbus_read_word(I2CBus *bus, uint8_t addr, uint8_t command)
 272 {
 273     uint16_t data;
 274     if (i2c_start_transfer(bus, addr, 0)) {
 275         return -1;
 276     }
 277     i2c_send(bus, command);
 278     if (i2c_start_transfer(bus, addr, 1)) {
 279         assert(0);
 280     }
 281     data = i2c_recv(bus);
 282     data |= i2c_recv(bus) << 8;
 283     i2c_nack(bus);
 284     i2c_end_transfer(bus);
 285     return data;
 286 }
 287
 288 int smbus_write_word(I2CBus *bus, uint8_t addr, uint8_t command, uint16_t data)
 289 {
 290     if (i2c_start_transfer(bus, addr, 0)) {
 291         return -1;
 292     }
 293     i2c_send(bus, command);
 294     i2c_send(bus, data & 0xff);
 295     i2c_send(bus, data >> 8);
 296     i2c_end_transfer(bus);
 297     return 0;
 298 }
 299
 300 int smbus_read_block(I2CBus *bus, uint8_t addr, uint8_t command, uint8_t *data)
 301 {
 302     int len;
 303     int i;
 304
 305     if (i2c_start_transfer(bus, addr, 0)) {
 306         return -1;
 307     }
 308     i2c_send(bus, command);
 309     if (i2c_start_transfer(bus, addr, 1)) {
 310         assert(0);
 311     }
 312     len = i2c_recv(bus);
 313     if (len > 32) {
 314         len = 0;
 315     }
 316     for (i = 0; i < len; i++) {
 317         data[i] = i2c_recv(bus);
 318     }
 319     i2c_nack(bus);
 320     i2c_end_transfer(bus);
 321     return len;
 322 }
 323
 324 int smbus_write_block(I2CBus *bus, uint8_t addr, uint8_t command, uint8_t *data,
 325                       int len)
 326 {
 327     int i;
 328
 329     if (len > 32)
 330         len = 32;
 331
 332     if (i2c_start_transfer(bus, addr, 0)) {
 333         return -1;
 334     }
 335     i2c_send(bus, command);
 336     i2c_send(bus, len);
 337     for (i = 0; i < len; i++) {
 338         i2c_send(bus, data[i]);
 339     }
 340     i2c_end_transfer(bus);
 341     return 0;
 342 }
 343
 344 static void smbus_device_class_init(ObjectClass *klass, void *data)
 345 {
 346     I2CSlaveClass *sc = I2C_SLAVE_CLASS(klass);
 347
 348     sc->init = smbus_device_init;
 349     sc->event = smbus_i2c_event;
 350     sc->recv = smbus_i2c_recv;
 351     sc->send = smbus_i2c_send;
 352 }
 353
 354 static const TypeInfo smbus_device_type_info = {
 355     .name = TYPE_SMBUS_DEVICE,
 356     .parent = TYPE_I2C_SLAVE,
 357     .instance_size = sizeof(SMBusDevice),
 358     .abstract = true,
 359     .class_size = sizeof(SMBusDeviceClass),
 360     .class_init = smbus_device_class_init,
 361 };
 362
 363 static void smbus_device_register_types(void)
 364 {
 365     type_register_static(&smbus_device_type_info);
 366 }
 367
 368 type_init(smbus_device_register_types)