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.
*/
#include "ssi.h"
typedef struct {
SSISlave ssidev;
qemu_irq interrupt;
uint8_t tb1, rb2, rb3;
int cycle;
int 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 void max111x_save(QEMUFile *f, void *opaque)
{
MAX111xState *s = (MAX111xState *) opaque;
int i;
qemu_put_8s(f, &s->tb1);
qemu_put_8s(f, &s->rb2);
qemu_put_8s(f, &s->rb3);
qemu_put_be32(f, s->inputs);
qemu_put_be32(f, s->com);
for (i = 0; i < s->inputs; i ++)
qemu_put_byte(f, s->input[i]);
}
static int max111x_load(QEMUFile *f, void *opaque, int version_id)
{
MAX111xState *s = (MAX111xState *) opaque;
int i;
qemu_get_8s(f, &s->tb1);
qemu_get_8s(f, &s->rb2);
qemu_get_8s(f, &s->rb3);
if (s->inputs != qemu_get_be32(f))
return -EINVAL;
s->com = qemu_get_be32(f);
for (i = 0; i < s->inputs; i ++)
s->input[i] = qemu_get_byte(f);
return 0;
}
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;
register_savevm("max111x", -1, 0, max111x_save, max111x_load, 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 SSISlaveInfo max1110_info = {
.qdev.name = "max1110",
.qdev.size = sizeof(MAX111xState),
.init = max1110_init,
.transfer = max111x_transfer
};
static SSISlaveInfo max1111_info = {
.qdev.name = "max1111",
.qdev.size = sizeof(MAX111xState),
.init = max1111_init,
.transfer = max111x_transfer
};
static void max111x_register_devices(void)
{
ssi_register_slave(&max1110_info);
ssi_register_slave(&max1111_info);
}
device_init(max111x_register_devices)