qemu/hw/max111x.c

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/*
* Maxim MAX1110/1111 ADC chip emulation.
*
* Copyright (c) 2006 Openedhand Ltd.
* Written by Andrzej Zaborowski <balrog@zabor.org>
*
* This code is licensed under the GNU GPLv2.
*
* Contributions after 2012-01-13 are licensed under the terms of the
* GNU GPL, version 2 or (at your option) any later version.
*/
#include "ssi.h"
typedef struct {
SSISlave ssidev;
qemu_irq interrupt;
uint8_t tb1, rb2, rb3;
int cycle;
uint8_t input[8];
int inputs, com;
} MAX111xState;
/* Control-byte bitfields */
#define CB_PD0 (1 << 0)
#define CB_PD1 (1 << 1)
#define CB_SGL (1 << 2)
#define CB_UNI (1 << 3)
#define CB_SEL0 (1 << 4)
#define CB_SEL1 (1 << 5)
#define CB_SEL2 (1 << 6)
#define CB_START (1 << 7)
#define CHANNEL_NUM(v, b0, b1, b2) \
((((v) >> (2 + (b0))) & 4) | \
(((v) >> (3 + (b1))) & 2) | \
(((v) >> (4 + (b2))) & 1))
static uint32_t max111x_read(MAX111xState *s)
{
if (!s->tb1)
return 0;
switch (s->cycle ++) {
case 1:
return s->rb2;
case 2:
return s->rb3;
}
return 0;
}
/* Interpret a control-byte */
static void max111x_write(MAX111xState *s, uint32_t value)
{
int measure, chan;
/* Ignore the value if START bit is zero */
if (!(value & CB_START))
return;
s->cycle = 0;
if (!(value & CB_PD1)) {
s->tb1 = 0;
return;
}
s->tb1 = value;
if (s->inputs == 8)
chan = CHANNEL_NUM(value, 1, 0, 2);
else
chan = CHANNEL_NUM(value & ~CB_SEL0, 0, 1, 2);
if (value & CB_SGL)
measure = s->input[chan] - s->com;
else
measure = s->input[chan] - s->input[chan ^ 1];
if (!(value & CB_UNI))
measure ^= 0x80;
s->rb2 = (measure >> 2) & 0x3f;
s->rb3 = (measure << 6) & 0xc0;
/* FIXME: When should the IRQ be lowered? */
qemu_irq_raise(s->interrupt);
}
static uint32_t max111x_transfer(SSISlave *dev, uint32_t value)
{
MAX111xState *s = FROM_SSI_SLAVE(MAX111xState, dev);
max111x_write(s, value);
return max111x_read(s);
}
static const VMStateDescription vmstate_max111x = {
.name = "max111x",
.version_id = 0,
.minimum_version_id = 0,
.minimum_version_id_old = 0,
.fields = (VMStateField[]) {
VMSTATE_UINT8(tb1, MAX111xState),
VMSTATE_UINT8(rb2, MAX111xState),
VMSTATE_UINT8(rb3, MAX111xState),
VMSTATE_INT32_EQUAL(inputs, MAX111xState),
VMSTATE_INT32(com, MAX111xState),
VMSTATE_ARRAY_INT32_UNSAFE(input, MAX111xState, inputs,
vmstate_info_uint8, uint8_t),
VMSTATE_END_OF_LIST()
}
};
static int max111x_init(SSISlave *dev, int inputs)
{
MAX111xState *s = FROM_SSI_SLAVE(MAX111xState, dev);
qdev_init_gpio_out(&dev->qdev, &s->interrupt, 1);
s->inputs = inputs;
/* TODO: add a user interface for setting these */
s->input[0] = 0xf0;
s->input[1] = 0xe0;
s->input[2] = 0xd0;
s->input[3] = 0xc0;
s->input[4] = 0xb0;
s->input[5] = 0xa0;
s->input[6] = 0x90;
s->input[7] = 0x80;
s->com = 0;
vmstate_register(&dev->qdev, -1, &vmstate_max111x, s);
return 0;
}
static int max1110_init(SSISlave *dev)
{
return max111x_init(dev, 8);
}
static int max1111_init(SSISlave *dev)
{
return max111x_init(dev, 4);
}
void max111x_set_input(DeviceState *dev, int line, uint8_t value)
{
MAX111xState *s = FROM_SSI_SLAVE(MAX111xState, SSI_SLAVE_FROM_QDEV(dev));
assert(line >= 0 && line < s->inputs);
s->input[line] = value;
}
static void max1110_class_init(ObjectClass *klass, void *data)
{
SSISlaveClass *k = SSI_SLAVE_CLASS(klass);
k->init = max1110_init;
k->transfer = max111x_transfer;
}
static TypeInfo max1110_info = {
.name = "max1110",
.parent = TYPE_SSI_SLAVE,
.instance_size = sizeof(MAX111xState),
.class_init = max1110_class_init,
};
static void max1111_class_init(ObjectClass *klass, void *data)
{
SSISlaveClass *k = SSI_SLAVE_CLASS(klass);
k->init = max1111_init;
k->transfer = max111x_transfer;
}
static TypeInfo max1111_info = {
.name = "max1111",
.parent = TYPE_SSI_SLAVE,
.instance_size = sizeof(MAX111xState),
.class_init = max1111_class_init,
};
static void max111x_register_devices(void)
{
type_register_static(&max1110_info);
type_register_static(&max1111_info);
}
device_init(max111x_register_devices)