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 /* Master device commands.  */
 206 int smbus_quick_command(I2CBus *bus, uint8_t addr, int read)
 207 {
 208     if (i2c_start_transfer(bus, addr, read)) {
 209         return -1;
 210     }
 211     i2c_end_transfer(bus);
 212     return 0;
 213 }
 214
 215 int smbus_receive_byte(I2CBus *bus, uint8_t addr)
 216 {
 217     uint8_t data;
 218
 219     if (i2c_start_transfer(bus, addr, 1)) {
 220         return -1;
 221     }
 222     data = i2c_recv(bus);
 223     i2c_nack(bus);
 224     i2c_end_transfer(bus);
 225     return data;
 226 }
 227
 228 int smbus_send_byte(I2CBus *bus, uint8_t addr, uint8_t data)
 229 {
 230     if (i2c_start_transfer(bus, addr, 0)) {
 231         return -1;
 232     }
 233     i2c_send(bus, data);
 234     i2c_end_transfer(bus);
 235     return 0;
 236 }
 237
 238 int smbus_read_byte(I2CBus *bus, uint8_t addr, uint8_t command)
 239 {
 240     uint8_t data;
 241     if (i2c_start_transfer(bus, addr, 0)) {
 242         return -1;
 243     }
 244     i2c_send(bus, command);
 245     if (i2c_start_transfer(bus, addr, 1)) {
 246         i2c_end_transfer(bus);
 247         return -1;
 248     }
 249     data = i2c_recv(bus);
 250     i2c_nack(bus);
 251     i2c_end_transfer(bus);
 252     return data;
 253 }
 254
 255 int smbus_write_byte(I2CBus *bus, uint8_t addr, uint8_t command, uint8_t data)
 256 {
 257     if (i2c_start_transfer(bus, addr, 0)) {
 258         return -1;
 259     }
 260     i2c_send(bus, command);
 261     i2c_send(bus, data);
 262     i2c_end_transfer(bus);
 263     return 0;
 264 }
 265
 266 int smbus_read_word(I2CBus *bus, uint8_t addr, uint8_t command)
 267 {
 268     uint16_t data;
 269     if (i2c_start_transfer(bus, addr, 0)) {
 270         return -1;
 271     }
 272     i2c_send(bus, command);
 273     if (i2c_start_transfer(bus, addr, 1)) {
 274         i2c_end_transfer(bus);
 275         return -1;
 276     }
 277     data = i2c_recv(bus);
 278     data |= i2c_recv(bus) << 8;
 279     i2c_nack(bus);
 280     i2c_end_transfer(bus);
 281     return data;
 282 }
 283
 284 int smbus_write_word(I2CBus *bus, uint8_t addr, uint8_t command, uint16_t data)
 285 {
 286     if (i2c_start_transfer(bus, addr, 0)) {
 287         return -1;
 288     }
 289     i2c_send(bus, command);
 290     i2c_send(bus, data & 0xff);
 291     i2c_send(bus, data >> 8);
 292     i2c_end_transfer(bus);
 293     return 0;
 294 }
 295
 296 int smbus_read_block(I2CBus *bus, uint8_t addr, uint8_t command, uint8_t *data,
 297                      int len, bool recv_len, bool send_cmd)
 298 {
 299     int rlen;
 300     int i;
 301
 302     if (send_cmd) {
 303         if (i2c_start_transfer(bus, addr, 0)) {
 304             return -1;
 305         }
 306         i2c_send(bus, command);
 307     }
 308     if (i2c_start_transfer(bus, addr, 1)) {
 309         if (send_cmd) {
 310             i2c_end_transfer(bus);
 311         }
 312         return -1;
 313     }
 314     if (recv_len) {
 315         rlen = i2c_recv(bus);
 316     } else {
 317         rlen = len;
 318     }
 319     if (rlen > len) {
 320         rlen = 0;
 321     }
 322     for (i = 0; i < rlen; i++) {
 323         data[i] = i2c_recv(bus);
 324     }
 325     i2c_nack(bus);
 326     i2c_end_transfer(bus);
 327     return rlen;
 328 }
 329
 330 int smbus_write_block(I2CBus *bus, uint8_t addr, uint8_t command, uint8_t *data,
 331                       int len, bool send_len)
 332 {
 333     int i;
 334
 335     if (len > 32)
 336         len = 32;
 337
 338     if (i2c_start_transfer(bus, addr, 0)) {
 339         return -1;
 340     }
 341     i2c_send(bus, command);
 342     if (send_len) {
 343         i2c_send(bus, len);
 344     }
 345     for (i = 0; i < len; i++) {
 346         i2c_send(bus, data[i]);
 347     }
 348     i2c_end_transfer(bus);
 349     return 0;
 350 }
 351
 352 static void smbus_device_class_init(ObjectClass *klass, void *data)
 353 {
 354     I2CSlaveClass *sc = I2C_SLAVE_CLASS(klass);
 355
 356     sc->event = smbus_i2c_event;
 357     sc->recv = smbus_i2c_recv;
 358     sc->send = smbus_i2c_send;
 359 }
 360
 361 static const TypeInfo smbus_device_type_info = {
 362     .name = TYPE_SMBUS_DEVICE,
 363     .parent = TYPE_I2C_SLAVE,
 364     .instance_size = sizeof(SMBusDevice),
 365     .abstract = true,
 366     .class_size = sizeof(SMBusDeviceClass),
 367     .class_init = smbus_device_class_init,
 368 };
 369
 370 static void smbus_device_register_types(void)
 371 {
 372     type_register_static(&smbus_device_type_info);
 373 }
 374
 375 type_init(smbus_device_register_types)