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/*
* QEMU SMBus device emulation.
*
* This code is a helper for SMBus device emulation. It implements an
* I2C device inteface and runs the SMBus protocol from the device
* point of view and maps those to simple calls to emulate.
*
* Copyright (c) 2007 CodeSourcery.
* Written by Paul Brook
*
* This code is licensed under the LGPL.
*/
/* TODO: Implement PEC. */
#include "qemu/osdep.h"
#include "hw/hw.h"
#include "hw/i2c/i2c.h"
#include "hw/i2c/smbus_slave.h"
//#define DEBUG_SMBUS 1
#ifdef DEBUG_SMBUS
#define DPRINTF(fmt, ...) \
do { printf("smbus(%02x): " fmt , dev->i2c.address, ## __VA_ARGS__); } while (0)
#define BADF(fmt, ...) \
do { fprintf(stderr, "smbus: error: " fmt , ## __VA_ARGS__); exit(1);} while (0)
#else
#define DPRINTF(fmt, ...) do {} while(0)
#define BADF(fmt, ...) \
do { fprintf(stderr, "smbus: error: " fmt , ## __VA_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)
{
SMBusDeviceClass *sc = SMBUS_DEVICE_GET_CLASS(dev);
DPRINTF("Quick Command %d\n", recv);
if (sc->quick_cmd) {
sc->quick_cmd(dev, recv);
}
}
static void smbus_do_write(SMBusDevice *dev)
{
SMBusDeviceClass *sc = SMBUS_DEVICE_GET_CLASS(dev);
if (dev->data_len == 0) {
smbus_do_quick_cmd(dev, 0);
} else if (dev->data_len == 1) {
DPRINTF("Send Byte\n");
if (sc->send_byte) {
sc->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 (sc->write_data) {
sc->write_data(dev, dev->command, dev->data_buf + 1,
dev->data_len - 1);
}
}
}
static int smbus_i2c_event(I2CSlave *s, enum i2c_event event)
{
SMBusDevice *dev = SMBUS_DEVICE(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;
}
}
return 0;
}
static uint8_t smbus_i2c_recv(I2CSlave *s)
{
SMBusDevice *dev = SMBUS_DEVICE(s);
SMBusDeviceClass *sc = SMBUS_DEVICE_GET_CLASS(dev);
uint8_t ret;
switch (dev->mode) {
case SMBUS_RECV_BYTE:
if (sc->receive_byte) {
ret = sc->receive_byte(dev);
} else {
ret = 0;
}
DPRINTF("Receive Byte %02x\n", ret);
dev->mode = SMBUS_DONE;
break;
case SMBUS_READ_DATA:
if (sc->read_data) {
ret = sc->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(I2CSlave *s, uint8_t data)
{
SMBusDevice *dev = SMBUS_DEVICE(s);
switch (dev->mode) {
case SMBUS_WRITE_DATA:
DPRINTF("Write data %02x\n", data);
if (dev->data_len >= sizeof(dev->data_buf)) {
BADF("Too many bytes sent\n");
} else {
dev->data_buf[dev->data_len++] = data;
}
break;
default:
BADF("Unexpected write in state %d\n", dev->mode);
break;
}
return 0;
}
static void smbus_device_class_init(ObjectClass *klass, void *data)
{
I2CSlaveClass *sc = I2C_SLAVE_CLASS(klass);
sc->event = smbus_i2c_event;
sc->recv = smbus_i2c_recv;
sc->send = smbus_i2c_send;
}
static const TypeInfo smbus_device_type_info = {
.name = TYPE_SMBUS_DEVICE,
.parent = TYPE_I2C_SLAVE,
.instance_size = sizeof(SMBusDevice),
.abstract = true,
.class_size = sizeof(SMBusDeviceClass),
.class_init = smbus_device_class_init,
};
static void smbus_device_register_types(void)
{
type_register_static(&smbus_device_type_info);
}
type_init(smbus_device_register_types)
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