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/*
* 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);
}
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