/*

 * QEMU SMBus device emulation.

 *

 * Copyright (c) 2007 CodeSourcery.

 * Written by Paul Brook

 *

 * This code is licenced under the LGPL.

 */

/* TODO: Implement PEC.  */

#include "hw.h"

#include "i2c.h"

#include "smbus.h"

//#define DEBUG_SMBUS 1

#ifdef DEBUG_SMBUS

#define DPRINTF(fmt, args...) \

do { printf("smbus(%02x): " fmt , dev->i2c.address, ##args); } while (0)

#define BADF(fmt, args...) \

do { fprintf(stderr, "smbus: error: " fmt , ##args); exit(1);} while (0)

#else

#define DPRINTF(fmt, args...) do {} while(0)

#define BADF(fmt, args...) \

do { fprintf(stderr, "smbus: error: " fmt , ##args);} while (0)

#endif

enum {

    SMBUS_IDLE,

    SMBUS_WRITE_DATA,

    SMBUS_RECV_BYTE,

    SMBUS_READ_DATA,

    SMBUS_DONE,

    SMBUS_CONFUSED = -1

};

static void smbus_do_quick_cmd(SMBusDevice *dev, int recv)

{

    DPRINTF("Quick Command %d\n", recv);

    if (dev->quick_cmd)

        dev->quick_cmd(dev, recv);

}

static void smbus_do_write(SMBusDevice *dev)

{

    if (dev->data_len == 0) {

        smbus_do_quick_cmd(dev, 0);

    } else if (dev->data_len == 1) {

        DPRINTF("Send Byte\n");

        if (dev->send_byte) {

            dev->send_byte(dev, dev->data_buf[0]);

        }

    } else {

        dev->command = dev->data_buf[0];

        DPRINTF("Command %d len %d\n", dev->command, dev->data_len - 1);

        if (dev->write_data) {

            dev->write_data(dev, dev->command, dev->data_buf + 1,

                            dev->data_len - 1);

        }

    }

}

static void smbus_i2c_event(i2c_slave *s, enum i2c_event event)

{

    SMBusDevice *dev = (SMBusDevice *)s;

    switch (event) {

    case I2C_START_SEND:

        switch (dev->mode) {

        case SMBUS_IDLE:

            DPRINTF("Incoming data\n");

            dev->mode = SMBUS_WRITE_DATA;

            break;

        default:

            BADF("Unexpected send start condition in state %d\n", dev->mode);

            dev->mode = SMBUS_CONFUSED;

            break;

        }

        break;

    case I2C_START_RECV:

        switch (dev->mode) {

        case SMBUS_IDLE:

            DPRINTF("Read mode\n");

            dev->mode = SMBUS_RECV_BYTE;

            break;

        case SMBUS_WRITE_DATA:

            if (dev->data_len == 0) {

                BADF("Read after write with no data\n");

                dev->mode = SMBUS_CONFUSED;

            } else {

                if (dev->data_len > 1) {

                    smbus_do_write(dev);

                } else {

                    dev->command = dev->data_buf[0];

                    DPRINTF("%02x: Command %d\n", dev->i2c.address,

                            dev->command);

                }

                DPRINTF("Read mode\n");

                dev->data_len = 0;

                dev->mode = SMBUS_READ_DATA;

            }

            break;

        default:

            BADF("Unexpected recv start condition in state %d\n", dev->mode);

            dev->mode = SMBUS_CONFUSED;

            break;

        }

        break;

    case I2C_FINISH:

        switch (dev->mode) {

        case SMBUS_WRITE_DATA:

            smbus_do_write(dev);

            break;

        case SMBUS_RECV_BYTE:

            smbus_do_quick_cmd(dev, 1);

            break;

        case SMBUS_READ_DATA:

            BADF("Unexpected stop during receive\n");

            break;

        default:

            /* Nothing to do.  */

            break;

        }

        dev->mode = SMBUS_IDLE;

        dev->data_len = 0;

        break;

    case I2C_NACK:

        switch (dev->mode) {

        case SMBUS_DONE:

            /* Nothing to do.  */

            break;

        case SMBUS_READ_DATA:

            dev->mode = SMBUS_DONE;

            break;

        default:

            BADF("Unexpected NACK in state %d\n", dev->mode);

            dev->mode = SMBUS_CONFUSED;

            break;

        }

    }

}

static int smbus_i2c_recv(i2c_slave *s)

{

    SMBusDevice *dev = (SMBusDevice *)s;

    int ret;

    switch (dev->mode) {

    case SMBUS_RECV_BYTE:

        if (dev->receive_byte) {

            ret = dev->receive_byte(dev);

        } else {

            ret = 0;

        }

        DPRINTF("Receive Byte %02x\n", ret);

        dev->mode = SMBUS_DONE;

        break;

    case SMBUS_READ_DATA:

        if (dev->read_data) {

            ret = dev->read_data(dev, dev->command, dev->data_len);

            dev->data_len++;

        } else {

            ret = 0;

        }

        DPRINTF("Read data %02x\n", ret);

        break;

    default:

        BADF("Unexpected read in state %d\n", dev->mode);

        dev->mode = SMBUS_CONFUSED;

        ret = 0;

        break;

    }

    return ret;

}

static int smbus_i2c_send(i2c_slave *s, uint8_t data)

{

    SMBusDevice *dev = (SMBusDevice *)s;

    switch (dev->mode) {

    case SMBUS_WRITE_DATA:

        DPRINTF("Write data %02x\n", data);

        dev->data_buf[dev->data_len++] = data;

        break;

    default:

        BADF("Unexpected write in state %d\n", dev->mode);

        break;

    }

    return 0;

}

SMBusDevice *smbus_device_init(i2c_bus *bus, int address, int size)

{

    SMBusDevice *dev;

    if (size < sizeof(SMBusDevice))

        hw_error("SMBus struct too small");

    dev = (SMBusDevice *)i2c_slave_init(bus, address, size);

    dev->i2c.event = smbus_i2c_event;

    dev->i2c.recv = smbus_i2c_recv;

    dev->i2c.send = smbus_i2c_send;

    return dev;

}

/* Master device commands.  */

void smbus_quick_command(i2c_bus *bus, int addr, int read)

{

    i2c_start_transfer(bus, addr, read);

    i2c_end_transfer(bus);

}

uint8_t smbus_receive_byte(i2c_bus *bus, int addr)

{

    uint8_t data;

    i2c_start_transfer(bus, addr, 1);

    data = i2c_recv(bus);

    i2c_nack(bus);

    i2c_end_transfer(bus);

    return data;

}

void smbus_send_byte(i2c_bus *bus, int addr, uint8_t data)

{

    i2c_start_transfer(bus, addr, 0);

    i2c_send(bus, data);

    i2c_end_transfer(bus);

}

uint8_t smbus_read_byte(i2c_bus *bus, int addr, uint8_t command)

{

    uint8_t data;

    i2c_start_transfer(bus, addr, 0);

    i2c_send(bus, command);

    i2c_start_transfer(bus, addr, 1);

    data = i2c_recv(bus);

    i2c_nack(bus);

    i2c_end_transfer(bus);

    return data;

}

void smbus_write_byte(i2c_bus *bus, int addr, uint8_t command, uint8_t data)

{

    i2c_start_transfer(bus, addr, 0);

    i2c_send(bus, command);

    i2c_send(bus, data);

    i2c_end_transfer(bus);

}

uint16_t smbus_read_word(i2c_bus *bus, int addr, uint8_t command)

{

    uint16_t data;

    i2c_start_transfer(bus, addr, 0);

    i2c_send(bus, command);

    i2c_start_transfer(bus, addr, 1);

    data = i2c_recv(bus);

    data |= i2c_recv(bus) << 8;

    i2c_nack(bus);

    i2c_end_transfer(bus);

    return data;

}

void smbus_write_word(i2c_bus *bus, int addr, uint8_t command, uint16_t data)

{

    i2c_start_transfer(bus, addr, 0);

    i2c_send(bus, command);

    i2c_send(bus, data & 0xff);

    i2c_send(bus, data >> 8);

    i2c_end_transfer(bus);

}

int smbus_read_block(i2c_bus *bus, int addr, uint8_t command, uint8_t *data)

{

    int len;

    int i;

    i2c_start_transfer(bus, addr, 0);

    i2c_send(bus, command);

    i2c_start_transfer(bus, addr, 1);

    len = i2c_recv(bus);

    if (len > 32)

        len = 0;

    for (i = 0; i < len; i++)

        data[i] = i2c_recv(bus);

    i2c_nack(bus);

    i2c_end_transfer(bus);

    return len;

}

void smbus_write_block(i2c_bus *bus, int addr, uint8_t command, uint8_t *data,

                       int len)

{

    int i;

    if (len > 32)

        len = 32;

    i2c_start_transfer(bus, addr, 0);

    i2c_send(bus, command);

    i2c_send(bus, len);

    for (i = 0; i < len; i++)

        i2c_send(bus, data[i]);

    i2c_end_transfer(bus);

}