root / hw / i2c / smbus.c @ 49ab747f
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/*
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* QEMU SMBus device emulation.
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*
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* Copyright (c) 2007 CodeSourcery.
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* Written by Paul Brook
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*
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* This code is licensed under the LGPL.
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*/
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/* TODO: Implement PEC. */
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#include "hw/hw.h" |
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#include "hw/i2c/i2c.h" |
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#include "hw/i2c/smbus.h" |
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//#define DEBUG_SMBUS 1
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#ifdef DEBUG_SMBUS
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#define DPRINTF(fmt, ...) \
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do { printf("smbus(%02x): " fmt , dev->i2c.address, ## __VA_ARGS__); } while (0) |
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#define BADF(fmt, ...) \
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do { fprintf(stderr, "smbus: error: " fmt , ## __VA_ARGS__); exit(1);} while (0) |
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#else
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#define DPRINTF(fmt, ...) do {} while(0) |
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#define BADF(fmt, ...) \
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do { fprintf(stderr, "smbus: error: " fmt , ## __VA_ARGS__);} while (0) |
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#endif
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enum {
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SMBUS_IDLE, |
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SMBUS_WRITE_DATA, |
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SMBUS_RECV_BYTE, |
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SMBUS_READ_DATA, |
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SMBUS_DONE, |
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SMBUS_CONFUSED = -1
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}; |
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static void smbus_do_quick_cmd(SMBusDevice *dev, int recv) |
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{
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SMBusDeviceClass *sc = SMBUS_DEVICE_GET_CLASS(dev); |
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DPRINTF("Quick Command %d\n", recv);
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if (sc->quick_cmd) {
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sc->quick_cmd(dev, recv); |
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} |
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} |
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static void smbus_do_write(SMBusDevice *dev) |
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{
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SMBusDeviceClass *sc = SMBUS_DEVICE_GET_CLASS(dev); |
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if (dev->data_len == 0) { |
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smbus_do_quick_cmd(dev, 0);
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} else if (dev->data_len == 1) { |
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DPRINTF("Send Byte\n");
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if (sc->send_byte) {
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sc->send_byte(dev, dev->data_buf[0]);
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} |
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} else {
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dev->command = dev->data_buf[0];
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DPRINTF("Command %d len %d\n", dev->command, dev->data_len - 1); |
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if (sc->write_data) {
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sc->write_data(dev, dev->command, dev->data_buf + 1,
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dev->data_len - 1);
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} |
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} |
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} |
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static void smbus_i2c_event(I2CSlave *s, enum i2c_event event) |
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{
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SMBusDevice *dev = SMBUS_DEVICE(s); |
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switch (event) {
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case I2C_START_SEND:
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switch (dev->mode) {
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case SMBUS_IDLE:
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DPRINTF("Incoming data\n");
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dev->mode = SMBUS_WRITE_DATA; |
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break;
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default:
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BADF("Unexpected send start condition in state %d\n", dev->mode);
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dev->mode = SMBUS_CONFUSED; |
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break;
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} |
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break;
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case I2C_START_RECV:
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switch (dev->mode) {
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case SMBUS_IDLE:
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DPRINTF("Read mode\n");
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dev->mode = SMBUS_RECV_BYTE; |
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break;
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case SMBUS_WRITE_DATA:
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if (dev->data_len == 0) { |
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BADF("Read after write with no data\n");
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dev->mode = SMBUS_CONFUSED; |
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} else {
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if (dev->data_len > 1) { |
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smbus_do_write(dev); |
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} else {
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dev->command = dev->data_buf[0];
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DPRINTF("%02x: Command %d\n", dev->i2c.address,
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dev->command); |
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} |
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DPRINTF("Read mode\n");
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dev->data_len = 0;
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dev->mode = SMBUS_READ_DATA; |
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} |
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break;
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default:
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BADF("Unexpected recv start condition in state %d\n", dev->mode);
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dev->mode = SMBUS_CONFUSED; |
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break;
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} |
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break;
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case I2C_FINISH:
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switch (dev->mode) {
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case SMBUS_WRITE_DATA:
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smbus_do_write(dev); |
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break;
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case SMBUS_RECV_BYTE:
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smbus_do_quick_cmd(dev, 1);
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break;
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case SMBUS_READ_DATA:
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BADF("Unexpected stop during receive\n");
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break;
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default:
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/* Nothing to do. */
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break;
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} |
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dev->mode = SMBUS_IDLE; |
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dev->data_len = 0;
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break;
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case I2C_NACK:
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switch (dev->mode) {
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case SMBUS_DONE:
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/* Nothing to do. */
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break;
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case SMBUS_READ_DATA:
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dev->mode = SMBUS_DONE; |
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break;
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default:
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BADF("Unexpected NACK in state %d\n", dev->mode);
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dev->mode = SMBUS_CONFUSED; |
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break;
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} |
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} |
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} |
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static int smbus_i2c_recv(I2CSlave *s) |
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{
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SMBusDevice *dev = SMBUS_DEVICE(s); |
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SMBusDeviceClass *sc = SMBUS_DEVICE_GET_CLASS(dev); |
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int ret;
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switch (dev->mode) {
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case SMBUS_RECV_BYTE:
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if (sc->receive_byte) {
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ret = sc->receive_byte(dev); |
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} else {
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ret = 0;
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} |
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DPRINTF("Receive Byte %02x\n", ret);
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dev->mode = SMBUS_DONE; |
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break;
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case SMBUS_READ_DATA:
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if (sc->read_data) {
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ret = sc->read_data(dev, dev->command, dev->data_len); |
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dev->data_len++; |
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} else {
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ret = 0;
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} |
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DPRINTF("Read data %02x\n", ret);
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break;
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default:
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BADF("Unexpected read in state %d\n", dev->mode);
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dev->mode = SMBUS_CONFUSED; |
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ret = 0;
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break;
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} |
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return ret;
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} |
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static int smbus_i2c_send(I2CSlave *s, uint8_t data) |
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{
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SMBusDevice *dev = SMBUS_DEVICE(s); |
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switch (dev->mode) {
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case SMBUS_WRITE_DATA:
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DPRINTF("Write data %02x\n", data);
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dev->data_buf[dev->data_len++] = data; |
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break;
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default:
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BADF("Unexpected write in state %d\n", dev->mode);
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break;
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} |
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return 0; |
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} |
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static int smbus_device_init(I2CSlave *i2c) |
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{
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SMBusDevice *dev = SMBUS_DEVICE(i2c); |
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SMBusDeviceClass *sc = SMBUS_DEVICE_GET_CLASS(dev); |
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return sc->init(dev);
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} |
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/* Master device commands. */
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void smbus_quick_command(i2c_bus *bus, uint8_t addr, int read) |
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{
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i2c_start_transfer(bus, addr, read); |
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i2c_end_transfer(bus); |
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} |
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uint8_t smbus_receive_byte(i2c_bus *bus, uint8_t addr) |
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{
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uint8_t data; |
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i2c_start_transfer(bus, addr, 1);
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data = i2c_recv(bus); |
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i2c_nack(bus); |
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i2c_end_transfer(bus); |
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return data;
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} |
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void smbus_send_byte(i2c_bus *bus, uint8_t addr, uint8_t data)
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{
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i2c_start_transfer(bus, addr, 0);
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i2c_send(bus, data); |
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i2c_end_transfer(bus); |
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} |
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uint8_t smbus_read_byte(i2c_bus *bus, uint8_t addr, uint8_t command) |
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{
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uint8_t data; |
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i2c_start_transfer(bus, addr, 0);
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i2c_send(bus, command); |
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i2c_start_transfer(bus, addr, 1);
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data = i2c_recv(bus); |
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i2c_nack(bus); |
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i2c_end_transfer(bus); |
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return data;
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} |
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void smbus_write_byte(i2c_bus *bus, uint8_t addr, uint8_t command, uint8_t data)
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{
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i2c_start_transfer(bus, addr, 0);
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i2c_send(bus, command); |
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i2c_send(bus, data); |
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i2c_end_transfer(bus); |
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} |
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uint16_t smbus_read_word(i2c_bus *bus, uint8_t addr, uint8_t command) |
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{
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uint16_t data; |
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i2c_start_transfer(bus, addr, 0);
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i2c_send(bus, command); |
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i2c_start_transfer(bus, addr, 1);
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data = i2c_recv(bus); |
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data |= i2c_recv(bus) << 8;
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i2c_nack(bus); |
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i2c_end_transfer(bus); |
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return data;
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} |
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void smbus_write_word(i2c_bus *bus, uint8_t addr, uint8_t command, uint16_t data)
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{
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i2c_start_transfer(bus, addr, 0);
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i2c_send(bus, command); |
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i2c_send(bus, data & 0xff);
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i2c_send(bus, data >> 8);
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i2c_end_transfer(bus); |
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} |
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int smbus_read_block(i2c_bus *bus, uint8_t addr, uint8_t command, uint8_t *data)
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{
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int len;
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int i;
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i2c_start_transfer(bus, addr, 0);
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i2c_send(bus, command); |
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i2c_start_transfer(bus, addr, 1);
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len = i2c_recv(bus); |
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if (len > 32) |
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len = 0;
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for (i = 0; i < len; i++) |
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data[i] = i2c_recv(bus); |
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i2c_nack(bus); |
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i2c_end_transfer(bus); |
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return len;
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} |
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void smbus_write_block(i2c_bus *bus, uint8_t addr, uint8_t command, uint8_t *data,
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int len)
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{
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int i;
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if (len > 32) |
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len = 32;
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i2c_start_transfer(bus, addr, 0);
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i2c_send(bus, command); |
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i2c_send(bus, len); |
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for (i = 0; i < len; i++) |
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i2c_send(bus, data[i]); |
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i2c_end_transfer(bus); |
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} |
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static void smbus_device_class_init(ObjectClass *klass, void *data) |
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{
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I2CSlaveClass *sc = I2C_SLAVE_CLASS(klass); |
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sc->init = smbus_device_init; |
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sc->event = smbus_i2c_event; |
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sc->recv = smbus_i2c_recv; |
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sc->send = smbus_i2c_send; |
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} |
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static const TypeInfo smbus_device_type_info = { |
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.name = TYPE_SMBUS_DEVICE, |
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.parent = TYPE_I2C_SLAVE, |
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.instance_size = sizeof(SMBusDevice),
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.abstract = true,
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.class_size = sizeof(SMBusDeviceClass),
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.class_init = smbus_device_class_init, |
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}; |
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static void smbus_device_register_types(void) |
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{
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type_register_static(&smbus_device_type_info); |
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} |
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type_init(smbus_device_register_types) |