qemu/hw/char/grlib_apbuart.c

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/*
* QEMU GRLIB APB UART Emulator
*
* Copyright (c) 2010-2011 AdaCore
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include "hw/sysbus.h"
#include "sysemu/char.h"
#include "trace.h"
#define UART_REG_SIZE 20 /* Size of memory mapped registers */
/* UART status register fields */
#define UART_DATA_READY (1 << 0)
#define UART_TRANSMIT_SHIFT_EMPTY (1 << 1)
#define UART_TRANSMIT_FIFO_EMPTY (1 << 2)
#define UART_BREAK_RECEIVED (1 << 3)
#define UART_OVERRUN (1 << 4)
#define UART_PARITY_ERROR (1 << 5)
#define UART_FRAMING_ERROR (1 << 6)
#define UART_TRANSMIT_FIFO_HALF (1 << 7)
#define UART_RECEIVE_FIFO_HALF (1 << 8)
#define UART_TRANSMIT_FIFO_FULL (1 << 9)
#define UART_RECEIVE_FIFO_FULL (1 << 10)
/* UART control register fields */
#define UART_RECEIVE_ENABLE (1 << 0)
#define UART_TRANSMIT_ENABLE (1 << 1)
#define UART_RECEIVE_INTERRUPT (1 << 2)
#define UART_TRANSMIT_INTERRUPT (1 << 3)
#define UART_PARITY_SELECT (1 << 4)
#define UART_PARITY_ENABLE (1 << 5)
#define UART_FLOW_CONTROL (1 << 6)
#define UART_LOOPBACK (1 << 7)
#define UART_EXTERNAL_CLOCK (1 << 8)
#define UART_RECEIVE_FIFO_INTERRUPT (1 << 9)
#define UART_TRANSMIT_FIFO_INTERRUPT (1 << 10)
#define UART_FIFO_DEBUG_MODE (1 << 11)
#define UART_OUTPUT_ENABLE (1 << 12)
#define UART_FIFO_AVAILABLE (1 << 31)
/* Memory mapped register offsets */
#define DATA_OFFSET 0x00
#define STATUS_OFFSET 0x04
#define CONTROL_OFFSET 0x08
#define SCALER_OFFSET 0x0C /* not supported */
#define FIFO_DEBUG_OFFSET 0x10 /* not supported */
#define FIFO_LENGTH 1024
#define TYPE_GRLIB_APB_UART "grlib,apbuart"
#define GRLIB_APB_UART(obj) \
OBJECT_CHECK(UART, (obj), TYPE_GRLIB_APB_UART)
typedef struct UART {
SysBusDevice parent_obj;
MemoryRegion iomem;
qemu_irq irq;
CharDriverState *chr;
/* registers */
uint32_t status;
uint32_t control;
/* FIFO */
char buffer[FIFO_LENGTH];
int len;
int current;
} UART;
static int uart_data_to_read(UART *uart)
{
return uart->current < uart->len;
}
static char uart_pop(UART *uart)
{
char ret;
if (uart->len == 0) {
uart->status &= ~UART_DATA_READY;
return 0;
}
ret = uart->buffer[uart->current++];
if (uart->current >= uart->len) {
/* Flush */
uart->len = 0;
uart->current = 0;
}
if (!uart_data_to_read(uart)) {
uart->status &= ~UART_DATA_READY;
}
return ret;
}
static void uart_add_to_fifo(UART *uart,
const uint8_t *buffer,
int length)
{
if (uart->len + length > FIFO_LENGTH) {
abort();
}
memcpy(uart->buffer + uart->len, buffer, length);
uart->len += length;
}
static int grlib_apbuart_can_receive(void *opaque)
{
UART *uart = opaque;
return FIFO_LENGTH - uart->len;
}
static void grlib_apbuart_receive(void *opaque, const uint8_t *buf, int size)
{
UART *uart = opaque;
if (uart->control & UART_RECEIVE_ENABLE) {
uart_add_to_fifo(uart, buf, size);
uart->status |= UART_DATA_READY;
if (uart->control & UART_RECEIVE_INTERRUPT) {
qemu_irq_pulse(uart->irq);
}
}
}
static void grlib_apbuart_event(void *opaque, int event)
{
trace_grlib_apbuart_event(event);
}
static uint64_t grlib_apbuart_read(void *opaque, hwaddr addr,
unsigned size)
{
UART *uart = opaque;
addr &= 0xff;
/* Unit registers */
switch (addr) {
case DATA_OFFSET:
case DATA_OFFSET + 3: /* when only one byte read */
return uart_pop(uart);
case STATUS_OFFSET:
/* Read Only */
return uart->status;
case CONTROL_OFFSET:
return uart->control;
case SCALER_OFFSET:
/* Not supported */
return 0;
default:
trace_grlib_apbuart_readl_unknown(addr);
return 0;
}
}
static void grlib_apbuart_write(void *opaque, hwaddr addr,
uint64_t value, unsigned size)
{
UART *uart = opaque;
unsigned char c = 0;
addr &= 0xff;
/* Unit registers */
switch (addr) {
case DATA_OFFSET:
case DATA_OFFSET + 3: /* When only one byte write */
/* Transmit when character device available and transmitter enabled */
if ((uart->chr) && (uart->control & UART_TRANSMIT_ENABLE)) {
c = value & 0xFF;
qemu_chr_fe_write(uart->chr, &c, 1);
/* Generate interrupt */
if (uart->control & UART_TRANSMIT_INTERRUPT) {
qemu_irq_pulse(uart->irq);
}
}
return;
case STATUS_OFFSET:
/* Read Only */
return;
case CONTROL_OFFSET:
uart->control = value;
return;
case SCALER_OFFSET:
/* Not supported */
return;
default:
break;
}
trace_grlib_apbuart_writel_unknown(addr, value);
}
static const MemoryRegionOps grlib_apbuart_ops = {
.write = grlib_apbuart_write,
.read = grlib_apbuart_read,
.endianness = DEVICE_NATIVE_ENDIAN,
};
static int grlib_apbuart_init(SysBusDevice *dev)
{
UART *uart = GRLIB_APB_UART(dev);
qemu_chr_add_handlers(uart->chr,
grlib_apbuart_can_receive,
grlib_apbuart_receive,
grlib_apbuart_event,
uart);
sysbus_init_irq(dev, &uart->irq);
memory_region_init_io(&uart->iomem, OBJECT(uart), &grlib_apbuart_ops, uart,
"uart", UART_REG_SIZE);
sysbus_init_mmio(dev, &uart->iomem);
return 0;
}
static void grlib_apbuart_reset(DeviceState *d)
{
UART *uart = GRLIB_APB_UART(d);
/* Transmitter FIFO and shift registers are always empty in QEMU */
uart->status = UART_TRANSMIT_FIFO_EMPTY | UART_TRANSMIT_SHIFT_EMPTY;
/* Everything is off */
uart->control = 0;
/* Flush receive FIFO */
uart->len = 0;
uart->current = 0;
}
static Property grlib_apbuart_properties[] = {
DEFINE_PROP_CHR("chrdev", UART, chr),
DEFINE_PROP_END_OF_LIST(),
};
static void grlib_apbuart_class_init(ObjectClass *klass, void *data)
{
DeviceClass *dc = DEVICE_CLASS(klass);
SysBusDeviceClass *k = SYS_BUS_DEVICE_CLASS(klass);
k->init = grlib_apbuart_init;
dc->reset = grlib_apbuart_reset;
dc->props = grlib_apbuart_properties;
}
static const TypeInfo grlib_apbuart_info = {
.name = TYPE_GRLIB_APB_UART,
.parent = TYPE_SYS_BUS_DEVICE,
.instance_size = sizeof(UART),
.class_init = grlib_apbuart_class_init,
};
static void grlib_apbuart_register_types(void)
{
type_register_static(&grlib_apbuart_info);
}
type_init(grlib_apbuart_register_types)