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/*
* QEMU ETRAX System Emulator
*
* Copyright (c) 2007 Edgar E. Iglesias, Axis Communications AB.
*
* 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 "sysbus.h"
#include "qemu-char.h"
#define D(x)
#define RW_TR_CTRL (0x00 / 4)
#define RW_TR_DMA_EN (0x04 / 4)
#define RW_REC_CTRL (0x08 / 4)
#define RW_DOUT (0x1c / 4)
#define RS_STAT_DIN (0x20 / 4)
#define R_STAT_DIN (0x24 / 4)
#define RW_INTR_MASK (0x2c / 4)
#define RW_ACK_INTR (0x30 / 4)
#define R_INTR (0x34 / 4)
#define R_MASKED_INTR (0x38 / 4)
#define R_MAX (0x3c / 4)
#define STAT_DAV 16
#define STAT_TR_IDLE 22
#define STAT_TR_RDY 24
struct etrax_serial
{
SysBusDevice busdev;
CharDriverState *chr;
qemu_irq irq;
int pending_tx;
uint8_t rx_fifo[16];
unsigned int rx_fifo_pos;
unsigned int rx_fifo_len;
/* Control registers. */
uint32_t regs[R_MAX];
};
static void ser_update_irq(struct etrax_serial *s)
{
if (s->rx_fifo_len) {
s->regs[R_INTR] |= 8;
} else {
s->regs[R_INTR] &= ~8;
}
s->regs[R_MASKED_INTR] = s->regs[R_INTR] & s->regs[RW_INTR_MASK];
qemu_set_irq(s->irq, !!s->regs[R_MASKED_INTR]);
}
static uint32_t ser_readl (void *opaque, target_phys_addr_t addr)
{
struct etrax_serial *s = opaque;
D(CPUState *env = s->env);
uint32_t r = 0;
addr >>= 2;
switch (addr)
{
case R_STAT_DIN:
r = s->rx_fifo[(s->rx_fifo_pos - s->rx_fifo_len) & 15];
if (s->rx_fifo_len) {
r |= 1 << STAT_DAV;
}
r |= 1 << STAT_TR_RDY;
r |= 1 << STAT_TR_IDLE;
break;
case RS_STAT_DIN:
r = s->rx_fifo[(s->rx_fifo_pos - s->rx_fifo_len) & 15];
if (s->rx_fifo_len) {
r |= 1 << STAT_DAV;
s->rx_fifo_len--;
}
r |= 1 << STAT_TR_RDY;
r |= 1 << STAT_TR_IDLE;
break;
default:
r = s->regs[addr];
D(printf ("%s " TARGET_FMT_plx "=%x\n", __func__, addr, r));
break;
}
return r;
}
static void
ser_writel (void *opaque, target_phys_addr_t addr, uint32_t value)
{
struct etrax_serial *s = opaque;
unsigned char ch = value;
D(CPUState *env = s->env);
D(printf ("%s " TARGET_FMT_plx "=%x\n", __func__, addr, value));
addr >>= 2;
switch (addr)
{
case RW_DOUT:
qemu_chr_write(s->chr, &ch, 1);
s->regs[R_INTR] |= 3;
s->pending_tx = 1;
s->regs[addr] = value;
break;
case RW_ACK_INTR:
if (s->pending_tx) {
value &= ~1;
s->pending_tx = 0;
D(printf("fixedup value=%x r_intr=%x\n", value, s->regs[R_INTR]));
}
s->regs[addr] = value;
s->regs[R_INTR] &= ~value;
D(printf("r_intr=%x\n", s->regs[R_INTR]));
break;
default:
s->regs[addr] = value;
break;
}
ser_update_irq(s);
}
static CPUReadMemoryFunc * const ser_read[] = {
NULL, NULL,
&ser_readl,
};
static CPUWriteMemoryFunc * const ser_write[] = {
NULL, NULL,
&ser_writel,
};
static void serial_receive(void *opaque, const uint8_t *buf, int size)
{
struct etrax_serial *s = opaque;
int i;
/* Got a byte. */
if (s->rx_fifo_len >= 16) {
printf("WARNING: UART dropped char.\n");
return;
}
for (i = 0; i < size; i++) {
s->rx_fifo[s->rx_fifo_pos] = buf[i];
s->rx_fifo_pos++;
s->rx_fifo_pos &= 15;
s->rx_fifo_len++;
}
ser_update_irq(s);
}
static int serial_can_receive(void *opaque)
{
struct etrax_serial *s = opaque;
int r;
/* Is the receiver enabled? */
if (!(s->regs[RW_REC_CTRL] & (1 << 3))) {
return 0;
}
r = sizeof(s->rx_fifo) - s->rx_fifo_len;
return r;
}
static void serial_event(void *opaque, int event)
{
}
static int etraxfs_ser_init(SysBusDevice *dev)
{
struct etrax_serial *s = FROM_SYSBUS(typeof (*s), dev);
int ser_regs;
/* transmitter begins ready and idle. */
s->regs[RS_STAT_DIN] |= (1 << STAT_TR_RDY);
s->regs[RS_STAT_DIN] |= (1 << STAT_TR_IDLE);
sysbus_init_irq(dev, &s->irq);
ser_regs = cpu_register_io_memory(ser_read, ser_write, s,
DEVICE_NATIVE_ENDIAN);
sysbus_init_mmio(dev, R_MAX * 4, ser_regs);
s->chr = qdev_init_chardev(&dev->qdev);
if (s->chr)
qemu_chr_add_handlers(s->chr,
serial_can_receive, serial_receive,
serial_event, s);
return 0;
}
static void etraxfs_serial_register(void)
{
sysbus_register_dev("etraxfs,serial", sizeof (struct etrax_serial),
etraxfs_ser_init);
}
device_init(etraxfs_serial_register)
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