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/*
* QEMU model of the Canon DIGIC UART block.
*
* Copyright (C) 2013 Antony Pavlov <antonynpavlov@gmail.com>
*
* This model is based on reverse engineering efforts
* made by CHDK (http://chdk.wikia.com) and
* Magic Lantern (http://www.magiclantern.fm) projects
* contributors.
*
* See "Serial terminal" docs here:
* http://magiclantern.wikia.com/wiki/Register_Map#Misc_Registers
*
* The QEMU model of the Milkymist UART block by Michael Walle
* is used as a template.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
*/
#include "qemu/osdep.h"
#include "hw/hw.h"
#include "hw/sysbus.h"
#include "chardev/char-fe.h"
#include "qemu/log.h"
#include "hw/char/digic-uart.h"
enum {
ST_RX_RDY = (1 << 0),
ST_TX_RDY = (1 << 1),
};
static uint64_t digic_uart_read(void *opaque, hwaddr addr,
unsigned size)
{
DigicUartState *s = opaque;
uint64_t ret = 0;
addr >>= 2;
switch (addr) {
case R_RX:
s->reg_st &= ~(ST_RX_RDY);
ret = s->reg_rx;
break;
case R_ST:
ret = s->reg_st;
break;
default:
qemu_log_mask(LOG_UNIMP,
"digic-uart: read access to unknown register 0x"
TARGET_FMT_plx, addr << 2);
}
return ret;
}
static void digic_uart_write(void *opaque, hwaddr addr, uint64_t value,
unsigned size)
{
DigicUartState *s = opaque;
unsigned char ch = value;
addr >>= 2;
switch (addr) {
case R_TX:
/* XXX this blocks entire thread. Rewrite to use
* qemu_chr_fe_write and background I/O callbacks */
qemu_chr_fe_write_all(&s->chr, &ch, 1);
break;
case R_ST:
/*
* Ignore write to R_ST.
*
* The point is that this register is actively used
* during receiving and transmitting symbols,
* but we don't know the function of most of bits.
*
* Ignoring writes to R_ST is only a simplification
* of the model. It has no perceptible side effects
* for existing guests.
*/
break;
default:
qemu_log_mask(LOG_UNIMP,
"digic-uart: write access to unknown register 0x"
TARGET_FMT_plx, addr << 2);
}
}
static const MemoryRegionOps uart_mmio_ops = {
.read = digic_uart_read,
.write = digic_uart_write,
.valid = {
.min_access_size = 4,
.max_access_size = 4,
},
.endianness = DEVICE_NATIVE_ENDIAN,
};
static int uart_can_rx(void *opaque)
{
DigicUartState *s = opaque;
return !(s->reg_st & ST_RX_RDY);
}
static void uart_rx(void *opaque, const uint8_t *buf, int size)
{
DigicUartState *s = opaque;
assert(uart_can_rx(opaque));
s->reg_st |= ST_RX_RDY;
s->reg_rx = *buf;
}
static void uart_event(void *opaque, int event)
{
}
static void digic_uart_reset(DeviceState *d)
{
DigicUartState *s = DIGIC_UART(d);
s->reg_rx = 0;
s->reg_st = ST_TX_RDY;
}
static void digic_uart_realize(DeviceState *dev, Error **errp)
{
DigicUartState *s = DIGIC_UART(dev);
qemu_chr_fe_set_handlers(&s->chr, uart_can_rx, uart_rx,
uart_event, s, NULL, true);
}
static void digic_uart_init(Object *obj)
{
DigicUartState *s = DIGIC_UART(obj);
memory_region_init_io(&s->regs_region, OBJECT(s), &uart_mmio_ops, s,
TYPE_DIGIC_UART, 0x18);
sysbus_init_mmio(SYS_BUS_DEVICE(obj), &s->regs_region);
}
static const VMStateDescription vmstate_digic_uart = {
.name = "digic-uart",
.version_id = 1,
.minimum_version_id = 1,
.fields = (VMStateField[]) {
VMSTATE_UINT32(reg_rx, DigicUartState),
VMSTATE_UINT32(reg_st, DigicUartState),
VMSTATE_END_OF_LIST()
}
};
static Property digic_uart_properties[] = {
DEFINE_PROP_CHR("chardev", DigicUartState, chr),
DEFINE_PROP_END_OF_LIST(),
};
static void digic_uart_class_init(ObjectClass *klass, void *data)
{
DeviceClass *dc = DEVICE_CLASS(klass);
dc->realize = digic_uart_realize;
dc->reset = digic_uart_reset;
dc->vmsd = &vmstate_digic_uart;
dc->props = digic_uart_properties;
}
static const TypeInfo digic_uart_info = {
.name = TYPE_DIGIC_UART,
.parent = TYPE_SYS_BUS_DEVICE,
.instance_size = sizeof(DigicUartState),
.instance_init = digic_uart_init,
.class_init = digic_uart_class_init,
};
static void digic_uart_register_types(void)
{
type_register_static(&digic_uart_info);
}
type_init(digic_uart_register_types)
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