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/*
* Example I2C device using asynchronous I2C send.
*
* Copyright (C) 2023 Samsung Electronics Co., Ltd. All Rights Reserved.
*
* This work is licensed under the terms of the GNU GPL, version 2. See
* the COPYING file in the top-level directory.
*
*/
#include "qemu/osdep.h"
#include "qemu/timer.h"
#include "qemu/main-loop.h"
#include "block/aio.h"
#include "hw/i2c/i2c.h"
#include "trace.h"
#define TYPE_I2C_ECHO "i2c-echo"
OBJECT_DECLARE_SIMPLE_TYPE(I2CEchoState, I2C_ECHO)
enum i2c_echo_state {
I2C_ECHO_STATE_IDLE,
I2C_ECHO_STATE_START_SEND,
I2C_ECHO_STATE_ACK,
};
typedef struct I2CEchoState {
I2CSlave parent_obj;
I2CBus *bus;
enum i2c_echo_state state;
QEMUBH *bh;
unsigned int pos;
uint8_t data[3];
} I2CEchoState;
static void i2c_echo_bh(void *opaque)
{
I2CEchoState *state = opaque;
switch (state->state) {
case I2C_ECHO_STATE_IDLE:
return;
case I2C_ECHO_STATE_START_SEND:
if (i2c_start_send_async(state->bus, state->data[0])) {
goto release_bus;
}
state->pos++;
state->state = I2C_ECHO_STATE_ACK;
return;
case I2C_ECHO_STATE_ACK:
if (state->pos > 2) {
break;
}
if (i2c_send_async(state->bus, state->data[state->pos++])) {
break;
}
return;
}
i2c_end_transfer(state->bus);
release_bus:
i2c_bus_release(state->bus);
state->state = I2C_ECHO_STATE_IDLE;
}
static int i2c_echo_event(I2CSlave *s, enum i2c_event event)
{
I2CEchoState *state = I2C_ECHO(s);
switch (event) {
case I2C_START_RECV:
state->pos = 0;
trace_i2c_echo_event(DEVICE(s)->canonical_path, "I2C_START_RECV");
break;
case I2C_START_SEND:
state->pos = 0;
trace_i2c_echo_event(DEVICE(s)->canonical_path, "I2C_START_SEND");
break;
case I2C_FINISH:
state->pos = 0;
state->state = I2C_ECHO_STATE_START_SEND;
i2c_bus_master(state->bus, state->bh);
trace_i2c_echo_event(DEVICE(s)->canonical_path, "I2C_FINISH");
break;
case I2C_NACK:
trace_i2c_echo_event(DEVICE(s)->canonical_path, "I2C_NACK");
break;
default:
trace_i2c_echo_event(DEVICE(s)->canonical_path, "UNHANDLED");
return -1;
}
return 0;
}
static uint8_t i2c_echo_recv(I2CSlave *s)
{
I2CEchoState *state = I2C_ECHO(s);
if (state->pos > 2) {
return 0xff;
}
trace_i2c_echo_recv(DEVICE(s)->canonical_path, state->data[state->pos]);
return state->data[state->pos++];
}
static int i2c_echo_send(I2CSlave *s, uint8_t data)
{
I2CEchoState *state = I2C_ECHO(s);
trace_i2c_echo_send(DEVICE(s)->canonical_path, data);
if (state->pos > 2) {
return -1;
}
state->data[state->pos++] = data;
return 0;
}
static void i2c_echo_realize(DeviceState *dev, Error **errp)
{
I2CEchoState *state = I2C_ECHO(dev);
BusState *bus = qdev_get_parent_bus(dev);
state->bus = I2C_BUS(bus);
state->bh = qemu_bh_new(i2c_echo_bh, state);
return;
}
static void i2c_echo_class_init(ObjectClass *oc, void *data)
{
I2CSlaveClass *sc = I2C_SLAVE_CLASS(oc);
DeviceClass *dc = DEVICE_CLASS(oc);
dc->realize = i2c_echo_realize;
sc->event = i2c_echo_event;
sc->recv = i2c_echo_recv;
sc->send = i2c_echo_send;
}
static const TypeInfo i2c_echo = {
.name = TYPE_I2C_ECHO,
.parent = TYPE_I2C_SLAVE,
.instance_size = sizeof(I2CEchoState),
.class_init = i2c_echo_class_init,
};
static void register_types(void)
{
type_register_static(&i2c_echo);
}
type_init(register_types);
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