qemu-e2k/hw/char/lm32_uart.c

311 lines
7.0 KiB
C

/*
* QEMU model of the LatticeMico32 UART block.
*
* Copyright (c) 2010 Michael Walle <michael@walle.cc>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, see <http://www.gnu.org/licenses/>.
*
*
* Specification available at:
* http://www.latticesemi.com/documents/mico32uart.pdf
*/
#include "qemu/osdep.h"
#include "hw/hw.h"
#include "hw/sysbus.h"
#include "trace.h"
#include "chardev/char-fe.h"
#include "qemu/error-report.h"
enum {
R_RXTX = 0,
R_IER,
R_IIR,
R_LCR,
R_MCR,
R_LSR,
R_MSR,
R_DIV,
R_MAX
};
enum {
IER_RBRI = (1<<0),
IER_THRI = (1<<1),
IER_RLSI = (1<<2),
IER_MSI = (1<<3),
};
enum {
IIR_STAT = (1<<0),
IIR_ID0 = (1<<1),
IIR_ID1 = (1<<2),
};
enum {
LCR_WLS0 = (1<<0),
LCR_WLS1 = (1<<1),
LCR_STB = (1<<2),
LCR_PEN = (1<<3),
LCR_EPS = (1<<4),
LCR_SP = (1<<5),
LCR_SB = (1<<6),
};
enum {
MCR_DTR = (1<<0),
MCR_RTS = (1<<1),
};
enum {
LSR_DR = (1<<0),
LSR_OE = (1<<1),
LSR_PE = (1<<2),
LSR_FE = (1<<3),
LSR_BI = (1<<4),
LSR_THRE = (1<<5),
LSR_TEMT = (1<<6),
};
enum {
MSR_DCTS = (1<<0),
MSR_DDSR = (1<<1),
MSR_TERI = (1<<2),
MSR_DDCD = (1<<3),
MSR_CTS = (1<<4),
MSR_DSR = (1<<5),
MSR_RI = (1<<6),
MSR_DCD = (1<<7),
};
#define TYPE_LM32_UART "lm32-uart"
#define LM32_UART(obj) OBJECT_CHECK(LM32UartState, (obj), TYPE_LM32_UART)
struct LM32UartState {
SysBusDevice parent_obj;
MemoryRegion iomem;
CharBackend chr;
qemu_irq irq;
uint32_t regs[R_MAX];
};
typedef struct LM32UartState LM32UartState;
static void uart_update_irq(LM32UartState *s)
{
unsigned int irq;
if ((s->regs[R_LSR] & (LSR_OE | LSR_PE | LSR_FE | LSR_BI))
&& (s->regs[R_IER] & IER_RLSI)) {
irq = 1;
s->regs[R_IIR] = IIR_ID1 | IIR_ID0;
} else if ((s->regs[R_LSR] & LSR_DR) && (s->regs[R_IER] & IER_RBRI)) {
irq = 1;
s->regs[R_IIR] = IIR_ID1;
} else if ((s->regs[R_LSR] & LSR_THRE) && (s->regs[R_IER] & IER_THRI)) {
irq = 1;
s->regs[R_IIR] = IIR_ID0;
} else if ((s->regs[R_MSR] & 0x0f) && (s->regs[R_IER] & IER_MSI)) {
irq = 1;
s->regs[R_IIR] = 0;
} else {
irq = 0;
s->regs[R_IIR] = IIR_STAT;
}
trace_lm32_uart_irq_state(irq);
qemu_set_irq(s->irq, irq);
}
static uint64_t uart_read(void *opaque, hwaddr addr,
unsigned size)
{
LM32UartState *s = opaque;
uint32_t r = 0;
addr >>= 2;
switch (addr) {
case R_RXTX:
r = s->regs[R_RXTX];
s->regs[R_LSR] &= ~LSR_DR;
uart_update_irq(s);
qemu_chr_fe_accept_input(&s->chr);
break;
case R_IIR:
case R_LSR:
case R_MSR:
r = s->regs[addr];
break;
case R_IER:
case R_LCR:
case R_MCR:
case R_DIV:
error_report("lm32_uart: read access to write only register 0x"
TARGET_FMT_plx, addr << 2);
break;
default:
error_report("lm32_uart: read access to unknown register 0x"
TARGET_FMT_plx, addr << 2);
break;
}
trace_lm32_uart_memory_read(addr << 2, r);
return r;
}
static void uart_write(void *opaque, hwaddr addr,
uint64_t value, unsigned size)
{
LM32UartState *s = opaque;
unsigned char ch = value;
trace_lm32_uart_memory_write(addr, value);
addr >>= 2;
switch (addr) {
case R_RXTX:
/* 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_IER:
case R_LCR:
case R_MCR:
case R_DIV:
s->regs[addr] = value;
break;
case R_IIR:
case R_LSR:
case R_MSR:
error_report("lm32_uart: write access to read only register 0x"
TARGET_FMT_plx, addr << 2);
break;
default:
error_report("lm32_uart: write access to unknown register 0x"
TARGET_FMT_plx, addr << 2);
break;
}
uart_update_irq(s);
}
static const MemoryRegionOps uart_ops = {
.read = uart_read,
.write = uart_write,
.endianness = DEVICE_NATIVE_ENDIAN,
.valid = {
.min_access_size = 4,
.max_access_size = 4,
},
};
static void uart_rx(void *opaque, const uint8_t *buf, int size)
{
LM32UartState *s = opaque;
if (s->regs[R_LSR] & LSR_DR) {
s->regs[R_LSR] |= LSR_OE;
}
s->regs[R_LSR] |= LSR_DR;
s->regs[R_RXTX] = *buf;
uart_update_irq(s);
}
static int uart_can_rx(void *opaque)
{
LM32UartState *s = opaque;
return !(s->regs[R_LSR] & LSR_DR);
}
static void uart_event(void *opaque, int event)
{
}
static void uart_reset(DeviceState *d)
{
LM32UartState *s = LM32_UART(d);
int i;
for (i = 0; i < R_MAX; i++) {
s->regs[i] = 0;
}
/* defaults */
s->regs[R_LSR] = LSR_THRE | LSR_TEMT;
}
static void lm32_uart_init(Object *obj)
{
LM32UartState *s = LM32_UART(obj);
SysBusDevice *dev = SYS_BUS_DEVICE(obj);
sysbus_init_irq(dev, &s->irq);
memory_region_init_io(&s->iomem, obj, &uart_ops, s,
"uart", R_MAX * 4);
sysbus_init_mmio(dev, &s->iomem);
}
static void lm32_uart_realize(DeviceState *dev, Error **errp)
{
LM32UartState *s = LM32_UART(dev);
qemu_chr_fe_set_handlers(&s->chr, uart_can_rx, uart_rx,
uart_event, NULL, s, NULL, true);
}
static const VMStateDescription vmstate_lm32_uart = {
.name = "lm32-uart",
.version_id = 1,
.minimum_version_id = 1,
.fields = (VMStateField[]) {
VMSTATE_UINT32_ARRAY(regs, LM32UartState, R_MAX),
VMSTATE_END_OF_LIST()
}
};
static Property lm32_uart_properties[] = {
DEFINE_PROP_CHR("chardev", LM32UartState, chr),
DEFINE_PROP_END_OF_LIST(),
};
static void lm32_uart_class_init(ObjectClass *klass, void *data)
{
DeviceClass *dc = DEVICE_CLASS(klass);
dc->reset = uart_reset;
dc->vmsd = &vmstate_lm32_uart;
dc->props = lm32_uart_properties;
dc->realize = lm32_uart_realize;
}
static const TypeInfo lm32_uart_info = {
.name = TYPE_LM32_UART,
.parent = TYPE_SYS_BUS_DEVICE,
.instance_size = sizeof(LM32UartState),
.instance_init = lm32_uart_init,
.class_init = lm32_uart_class_init,
};
static void lm32_uart_register_types(void)
{
type_register_static(&lm32_uart_info);
}
type_init(lm32_uart_register_types)