hw/smbus.c

   1 /*
   2  * QEMU SMBus device emulation.
   3  *
   4  * Copyright (c) 2007 CodeSourcery.
   5  * Written by Paul Brook
   6  *
   7  * This code is licenced under the LGPL.
   8  */
   9
  10 /* TODO: Implement PEC.  */
  11
  12 #include "hw.h"
  13 #include "i2c.h"
  14 #include "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     SMBusDeviceInfo *t = container_of(dev->i2c.info, SMBusDeviceInfo, i2c);
  41
  42     DPRINTF("Quick Command %d\n", recv);
  43     if (t->quick_cmd)
  44         t->quick_cmd(dev, recv);
  45 }
  46
  47 static void smbus_do_write(SMBusDevice *dev)
  48 {
  49     SMBusDeviceInfo *t = container_of(dev->i2c.info, SMBusDeviceInfo, i2c);
  50
  51     if (dev->data_len == 0) {
  52         smbus_do_quick_cmd(dev, 0);
  53     } else if (dev->data_len == 1) {
  54         DPRINTF("Send Byte\n");
  55         if (t->send_byte) {
  56             t->send_byte(dev, dev->data_buf[0]);
  57         }
  58     } else {
  59         dev->command = dev->data_buf[0];
  60         DPRINTF("Command %d len %d\n", dev->command, dev->data_len - 1);
  61         if (t->write_data) {
  62             t->write_data(dev, dev->command, dev->data_buf + 1,
  63                           dev->data_len - 1);
  64         }
  65     }
  66 }
  67
  68 static void smbus_i2c_event(i2c_slave *s, enum i2c_event event)
  69 {
  70     SMBusDevice *dev = FROM_I2C_SLAVE(SMBusDevice, s);
  71
  72     switch (event) {
  73     case I2C_START_SEND:
  74         switch (dev->mode) {
  75         case SMBUS_IDLE:
  76             DPRINTF("Incoming data\n");
  77             dev->mode = SMBUS_WRITE_DATA;
  78             break;
  79         default:
  80             BADF("Unexpected send start condition in state %d\n", dev->mode);
  81             dev->mode = SMBUS_CONFUSED;
  82             break;
  83         }
  84         break;
  85
  86     case I2C_START_RECV:
  87         switch (dev->mode) {
  88         case SMBUS_IDLE:
  89             DPRINTF("Read mode\n");
  90             dev->mode = SMBUS_RECV_BYTE;
  91             break;
  92         case SMBUS_WRITE_DATA:
  93             if (dev->data_len == 0) {
  94                 BADF("Read after write with no data\n");
  95                 dev->mode = SMBUS_CONFUSED;
  96             } else {
  97                 if (dev->data_len > 1) {
  98                     smbus_do_write(dev);
  99                 } else {
 100                     dev->command = dev->data_buf[0];
 101                     DPRINTF("%02x: Command %d\n", dev->i2c.address,
 102                             dev->command);
 103                 }
 104                 DPRINTF("Read mode\n");
 105                 dev->data_len = 0;
 106                 dev->mode = SMBUS_READ_DATA;
 107             }
 108             break;
 109         default:
 110             BADF("Unexpected recv start condition in state %d\n", dev->mode);
 111             dev->mode = SMBUS_CONFUSED;
 112             break;
 113         }
 114         break;
 115
 116     case I2C_FINISH:
 117         switch (dev->mode) {
 118         case SMBUS_WRITE_DATA:
 119             smbus_do_write(dev);
 120             break;
 121         case SMBUS_RECV_BYTE:
 122             smbus_do_quick_cmd(dev, 1);
 123             break;
 124         case SMBUS_READ_DATA:
 125             BADF("Unexpected stop during receive\n");
 126             break;
 127         default:
 128             /* Nothing to do.  */
 129             break;
 130         }
 131         dev->mode = SMBUS_IDLE;
 132         dev->data_len = 0;
 133         break;
 134
 135     case I2C_NACK:
 136         switch (dev->mode) {
 137         case SMBUS_DONE:
 138             /* Nothing to do.  */
 139             break;
 140         case SMBUS_READ_DATA:
 141             dev->mode = SMBUS_DONE;
 142             break;
 143         default:
 144             BADF("Unexpected NACK in state %d\n", dev->mode);
 145             dev->mode = SMBUS_CONFUSED;
 146             break;
 147         }
 148     }
 149 }
 150
 151 static int smbus_i2c_recv(i2c_slave *s)
 152 {
 153     SMBusDeviceInfo *t = container_of(s->info, SMBusDeviceInfo, i2c);
 154     SMBusDevice *dev = FROM_I2C_SLAVE(SMBusDevice, s);
 155     int ret;
 156
 157     switch (dev->mode) {
 158     case SMBUS_RECV_BYTE:
 159         if (t->receive_byte) {
 160             ret = t->receive_byte(dev);
 161         } else {
 162             ret = 0;
 163         }
 164         DPRINTF("Receive Byte %02x\n", ret);
 165         dev->mode = SMBUS_DONE;
 166         break;
 167     case SMBUS_READ_DATA:
 168         if (t->read_data) {
 169             ret = t->read_data(dev, dev->command, dev->data_len);
 170             dev->data_len++;
 171         } else {
 172             ret = 0;
 173         }
 174         DPRINTF("Read data %02x\n", ret);
 175         break;
 176     default:
 177         BADF("Unexpected read in state %d\n", dev->mode);
 178         dev->mode = SMBUS_CONFUSED;
 179         ret = 0;
 180         break;
 181     }
 182     return ret;
 183 }
 184
 185 static int smbus_i2c_send(i2c_slave *s, uint8_t data)
 186 {
 187     SMBusDevice *dev = FROM_I2C_SLAVE(SMBusDevice, s);
 188
 189     switch (dev->mode) {
 190     case SMBUS_WRITE_DATA:
 191         DPRINTF("Write data %02x\n", data);
 192         dev->data_buf[dev->data_len++] = data;
 193         break;
 194     default:
 195         BADF("Unexpected write in state %d\n", dev->mode);
 196         break;
 197     }
 198     return 0;
 199 }
 200
 201 static void smbus_device_init(i2c_slave *i2c)
 202 {
 203     SMBusDeviceInfo *t = container_of(i2c->info, SMBusDeviceInfo, i2c);
 204     SMBusDevice *dev = FROM_I2C_SLAVE(SMBusDevice, i2c);
 205
 206     t->init(dev);
 207 }
 208
 209 void smbus_register_device(const char *name, int size, SMBusDeviceInfo *info)
 210 {
 211     assert(size >= sizeof(SMBusDevice));
 212     info->i2c.init = smbus_device_init;
 213     info->i2c.event = smbus_i2c_event;
 214     info->i2c.recv = smbus_i2c_recv;
 215     info->i2c.send = smbus_i2c_send;
 216     i2c_register_slave(name, size, &info->i2c);
 217 }
 218
 219 /* Master device commands.  */
 220 void smbus_quick_command(i2c_bus *bus, int addr, int read)
 221 {
 222     i2c_start_transfer(bus, addr, read);
 223     i2c_end_transfer(bus);
 224 }
 225
 226 uint8_t smbus_receive_byte(i2c_bus *bus, int addr)
 227 {
 228     uint8_t data;
 229
 230     i2c_start_transfer(bus, addr, 1);
 231     data = i2c_recv(bus);
 232     i2c_nack(bus);
 233     i2c_end_transfer(bus);
 234     return data;
 235 }
 236
 237 void smbus_send_byte(i2c_bus *bus, int addr, uint8_t data)
 238 {
 239     i2c_start_transfer(bus, addr, 0);
 240     i2c_send(bus, data);
 241     i2c_end_transfer(bus);
 242 }
 243
 244 uint8_t smbus_read_byte(i2c_bus *bus, int addr, uint8_t command)
 245 {
 246     uint8_t data;
 247     i2c_start_transfer(bus, addr, 0);
 248     i2c_send(bus, command);
 249     i2c_start_transfer(bus, addr, 1);
 250     data = i2c_recv(bus);
 251     i2c_nack(bus);
 252     i2c_end_transfer(bus);
 253     return data;
 254 }
 255
 256 void smbus_write_byte(i2c_bus *bus, int addr, uint8_t command, uint8_t data)
 257 {
 258     i2c_start_transfer(bus, addr, 0);
 259     i2c_send(bus, command);
 260     i2c_send(bus, data);
 261     i2c_end_transfer(bus);
 262 }
 263
 264 uint16_t smbus_read_word(i2c_bus *bus, int addr, uint8_t command)
 265 {
 266     uint16_t data;
 267     i2c_start_transfer(bus, addr, 0);
 268     i2c_send(bus, command);
 269     i2c_start_transfer(bus, addr, 1);
 270     data = i2c_recv(bus);
 271     data |= i2c_recv(bus) << 8;
 272     i2c_nack(bus);
 273     i2c_end_transfer(bus);
 274     return data;
 275 }
 276
 277 void smbus_write_word(i2c_bus *bus, int addr, uint8_t command, uint16_t data)
 278 {
 279     i2c_start_transfer(bus, addr, 0);
 280     i2c_send(bus, command);
 281     i2c_send(bus, data & 0xff);
 282     i2c_send(bus, data >> 8);
 283     i2c_end_transfer(bus);
 284 }
 285
 286 int smbus_read_block(i2c_bus *bus, int addr, uint8_t command, uint8_t *data)
 287 {
 288     int len;
 289     int i;
 290
 291     i2c_start_transfer(bus, addr, 0);
 292     i2c_send(bus, command);
 293     i2c_start_transfer(bus, addr, 1);
 294     len = i2c_recv(bus);
 295     if (len > 32)
 296         len = 0;
 297     for (i = 0; i < len; i++)
 298         data[i] = i2c_recv(bus);
 299     i2c_nack(bus);
 300     i2c_end_transfer(bus);
 301     return len;
 302 }
 303
 304 void smbus_write_block(i2c_bus *bus, int addr, uint8_t command, uint8_t *data,
 305                        int len)
 306 {
 307     int i;
 308
 309     if (len > 32)
 310         len = 32;
 311
 312     i2c_start_transfer(bus, addr, 0);
 313     i2c_send(bus, command);
 314     i2c_send(bus, len);
 315     for (i = 0; i < len; i++)
 316         i2c_send(bus, data[i]);
 317     i2c_end_transfer(bus);
 318 }