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qemu/hw/serial.c
balrog b2a5160c9f Add serial loopback mode (patch from Hervé Poussineau). 
git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@3973 c046a42c-6fe2-441c-8c8c-71466251a162
2008-02-10 13:40:52 +00:00

504 lines
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C
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/*
* QEMU 16450 UART emulation
*
* Copyright (c) 2003-2004 Fabrice Bellard
*
* 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.h"
#include "qemu-char.h"
#include "isa.h"
#include "pc.h"
//#define DEBUG_SERIAL
#define UART_LCR_DLAB 0x80 /* Divisor latch access bit */
#define UART_IER_MSI 0x08 /* Enable Modem status interrupt */
#define UART_IER_RLSI 0x04 /* Enable receiver line status interrupt */
#define UART_IER_THRI 0x02 /* Enable Transmitter holding register int. */
#define UART_IER_RDI 0x01 /* Enable receiver data interrupt */
#define UART_IIR_NO_INT 0x01 /* No interrupts pending */
#define UART_IIR_ID 0x06 /* Mask for the interrupt ID */
#define UART_IIR_MSI 0x00 /* Modem status interrupt */
#define UART_IIR_THRI 0x02 /* Transmitter holding register empty */
#define UART_IIR_RDI 0x04 /* Receiver data interrupt */
#define UART_IIR_RLSI 0x06 /* Receiver line status interrupt */
/*
* These are the definitions for the Modem Control Register
*/
#define UART_MCR_LOOP 0x10 /* Enable loopback test mode */
#define UART_MCR_OUT2 0x08 /* Out2 complement */
#define UART_MCR_OUT1 0x04 /* Out1 complement */
#define UART_MCR_RTS 0x02 /* RTS complement */
#define UART_MCR_DTR 0x01 /* DTR complement */
/*
* These are the definitions for the Modem Status Register
*/
#define UART_MSR_DCD 0x80 /* Data Carrier Detect */
#define UART_MSR_RI 0x40 /* Ring Indicator */
#define UART_MSR_DSR 0x20 /* Data Set Ready */
#define UART_MSR_CTS 0x10 /* Clear to Send */
#define UART_MSR_DDCD 0x08 /* Delta DCD */
#define UART_MSR_TERI 0x04 /* Trailing edge ring indicator */
#define UART_MSR_DDSR 0x02 /* Delta DSR */
#define UART_MSR_DCTS 0x01 /* Delta CTS */
#define UART_MSR_ANY_DELTA 0x0F /* Any of the delta bits! */
#define UART_LSR_TEMT 0x40 /* Transmitter empty */
#define UART_LSR_THRE 0x20 /* Transmit-hold-register empty */
#define UART_LSR_BI 0x10 /* Break interrupt indicator */
#define UART_LSR_FE 0x08 /* Frame error indicator */
#define UART_LSR_PE 0x04 /* Parity error indicator */
#define UART_LSR_OE 0x02 /* Overrun error indicator */
#define UART_LSR_DR 0x01 /* Receiver data ready */
struct SerialState {
uint16_t divider;
uint8_t rbr; /* receive register */
uint8_t ier;
uint8_t iir; /* read only */
uint8_t lcr;
uint8_t mcr;
uint8_t lsr; /* read only */
uint8_t msr; /* read only */
uint8_t scr;
/* NOTE: this hidden state is necessary for tx irq generation as
it can be reset while reading iir */
int thr_ipending;
qemu_irq irq;
CharDriverState *chr;
int last_break_enable;
target_phys_addr_t base;
int it_shift;
};
static void serial_receive_byte(SerialState *s, int ch);
static void serial_update_irq(SerialState *s)
{
if ((s->lsr & UART_LSR_DR) && (s->ier & UART_IER_RDI)) {
s->iir = UART_IIR_RDI;
} else if (s->thr_ipending && (s->ier & UART_IER_THRI)) {
s->iir = UART_IIR_THRI;
} else {
s->iir = UART_IIR_NO_INT;
}
if (s->iir != UART_IIR_NO_INT) {
qemu_irq_raise(s->irq);
} else {
qemu_irq_lower(s->irq);
}
}
static void serial_update_parameters(SerialState *s)
{
int speed, parity, data_bits, stop_bits;
QEMUSerialSetParams ssp;
if (s->lcr & 0x08) {
if (s->lcr & 0x10)
parity = 'E';
else
parity = 'O';
} else {
parity = 'N';
}
if (s->lcr & 0x04)
stop_bits = 2;
else
stop_bits = 1;
data_bits = (s->lcr & 0x03) + 5;
if (s->divider == 0)
return;
speed = 115200 / s->divider;
ssp.speed = speed;
ssp.parity = parity;
ssp.data_bits = data_bits;
ssp.stop_bits = stop_bits;
qemu_chr_ioctl(s->chr, CHR_IOCTL_SERIAL_SET_PARAMS, &ssp);
#if 0
printf("speed=%d parity=%c data=%d stop=%d\n",
speed, parity, data_bits, stop_bits);
#endif
}
static void serial_ioport_write(void *opaque, uint32_t addr, uint32_t val)
{
SerialState *s = opaque;
unsigned char ch;
addr &= 7;
#ifdef DEBUG_SERIAL
printf("serial: write addr=0x%02x val=0x%02x\n", addr, val);
#endif
switch(addr) {
default:
case 0:
if (s->lcr & UART_LCR_DLAB) {
s->divider = (s->divider & 0xff00) | val;
serial_update_parameters(s);
} else {
s->thr_ipending = 0;
s->lsr &= ~UART_LSR_THRE;
serial_update_irq(s);
ch = val;
if (!(s->mcr & UART_MCR_LOOP)) {
/* when not in loopback mode, send the char */
qemu_chr_write(s->chr, &ch, 1);
}
s->thr_ipending = 1;
s->lsr |= UART_LSR_THRE;
s->lsr |= UART_LSR_TEMT;
serial_update_irq(s);
if (s->mcr & UART_MCR_LOOP) {
/* in loopback mode, say that we just received a char */
serial_receive_byte(s, ch);
}
}
break;
case 1:
if (s->lcr & UART_LCR_DLAB) {
s->divider = (s->divider & 0x00ff) | (val << 8);
serial_update_parameters(s);
} else {
s->ier = val & 0x0f;
if (s->lsr & UART_LSR_THRE) {
s->thr_ipending = 1;
}
serial_update_irq(s);
}
break;
case 2:
break;
case 3:
{
int break_enable;
s->lcr = val;
serial_update_parameters(s);
break_enable = (val >> 6) & 1;
if (break_enable != s->last_break_enable) {
s->last_break_enable = break_enable;
qemu_chr_ioctl(s->chr, CHR_IOCTL_SERIAL_SET_BREAK,
&break_enable);
}
}
break;
case 4:
s->mcr = val & 0x1f;
break;
case 5:
break;
case 6:
break;
case 7:
s->scr = val;
break;
}
}
static uint32_t serial_ioport_read(void *opaque, uint32_t addr)
{
SerialState *s = opaque;
uint32_t ret;
addr &= 7;
switch(addr) {
default:
case 0:
if (s->lcr & UART_LCR_DLAB) {
ret = s->divider & 0xff;
} else {
ret = s->rbr;
s->lsr &= ~(UART_LSR_DR | UART_LSR_BI);
serial_update_irq(s);
if (!(s->mcr & UART_MCR_LOOP)) {
/* in loopback mode, don't receive any data */
qemu_chr_accept_input(s->chr);
}
}
break;
case 1:
if (s->lcr & UART_LCR_DLAB) {
ret = (s->divider >> 8) & 0xff;
} else {
ret = s->ier;
}
break;
case 2:
ret = s->iir;
/* reset THR pending bit */
if ((ret & 0x7) == UART_IIR_THRI)
s->thr_ipending = 0;
serial_update_irq(s);
break;
case 3:
ret = s->lcr;
break;
case 4:
ret = s->mcr;
break;
case 5:
ret = s->lsr;
break;
case 6:
if (s->mcr & UART_MCR_LOOP) {
/* in loopback, the modem output pins are connected to the
inputs */
ret = (s->mcr & 0x0c) << 4;
ret |= (s->mcr & 0x02) << 3;
ret |= (s->mcr & 0x01) << 5;
} else {
ret = s->msr;
}
break;
case 7:
ret = s->scr;
break;
}
#ifdef DEBUG_SERIAL
printf("serial: read addr=0x%02x val=0x%02x\n", addr, ret);
#endif
return ret;
}
static int serial_can_receive(SerialState *s)
{
return !(s->lsr & UART_LSR_DR);
}
static void serial_receive_byte(SerialState *s, int ch)
{
s->rbr = ch;
s->lsr |= UART_LSR_DR;
serial_update_irq(s);
}
static void serial_receive_break(SerialState *s)
{
s->rbr = 0;
s->lsr |= UART_LSR_BI | UART_LSR_DR;
serial_update_irq(s);
}
static int serial_can_receive1(void *opaque)
{
SerialState *s = opaque;
return serial_can_receive(s);
}
static void serial_receive1(void *opaque, const uint8_t *buf, int size)
{
SerialState *s = opaque;
serial_receive_byte(s, buf[0]);
}
static void serial_event(void *opaque, int event)
{
SerialState *s = opaque;
if (event == CHR_EVENT_BREAK)
serial_receive_break(s);
}
static void serial_save(QEMUFile *f, void *opaque)
{
SerialState *s = opaque;
qemu_put_be16s(f,&s->divider);
qemu_put_8s(f,&s->rbr);
qemu_put_8s(f,&s->ier);
qemu_put_8s(f,&s->iir);
qemu_put_8s(f,&s->lcr);
qemu_put_8s(f,&s->mcr);
qemu_put_8s(f,&s->lsr);
qemu_put_8s(f,&s->msr);
qemu_put_8s(f,&s->scr);
}
static int serial_load(QEMUFile *f, void *opaque, int version_id)
{
SerialState *s = opaque;
if(version_id > 2)
return -EINVAL;
if (version_id >= 2)
qemu_get_be16s(f, &s->divider);
else
s->divider = qemu_get_byte(f);
qemu_get_8s(f,&s->rbr);
qemu_get_8s(f,&s->ier);
qemu_get_8s(f,&s->iir);
qemu_get_8s(f,&s->lcr);
qemu_get_8s(f,&s->mcr);
qemu_get_8s(f,&s->lsr);
qemu_get_8s(f,&s->msr);
qemu_get_8s(f,&s->scr);
return 0;
}
static void serial_reset(void *opaque)
{
SerialState *s = opaque;
s->divider = 0;
s->rbr = 0;
s->ier = 0;
s->iir = UART_IIR_NO_INT;
s->lcr = 0;
s->mcr = 0;
s->lsr = UART_LSR_TEMT | UART_LSR_THRE;
s->msr = UART_MSR_DCD | UART_MSR_DSR | UART_MSR_CTS;
s->scr = 0;
s->thr_ipending = 0;
s->last_break_enable = 0;
qemu_irq_lower(s->irq);
}
/* If fd is zero, it means that the serial device uses the console */
SerialState *serial_init(int base, qemu_irq irq, CharDriverState *chr)
{
SerialState *s;
s = qemu_mallocz(sizeof(SerialState));
if (!s)
return NULL;
s->irq = irq;
qemu_register_reset(serial_reset, s);
serial_reset(s);
register_savevm("serial", base, 2, serial_save, serial_load, s);
register_ioport_write(base, 8, 1, serial_ioport_write, s);
register_ioport_read(base, 8, 1, serial_ioport_read, s);
s->chr = chr;
qemu_chr_add_handlers(chr, serial_can_receive1, serial_receive1,
serial_event, s);
return s;
}
/* Memory mapped interface */
uint32_t serial_mm_readb (void *opaque, target_phys_addr_t addr)
{
SerialState *s = opaque;
return serial_ioport_read(s, (addr - s->base) >> s->it_shift) & 0xFF;
}
void serial_mm_writeb (void *opaque,
target_phys_addr_t addr, uint32_t value)
{
SerialState *s = opaque;
serial_ioport_write(s, (addr - s->base) >> s->it_shift, value & 0xFF);
}
uint32_t serial_mm_readw (void *opaque, target_phys_addr_t addr)
{
SerialState *s = opaque;
uint32_t val;
val = serial_ioport_read(s, (addr - s->base) >> s->it_shift) & 0xFFFF;
#ifdef TARGET_WORDS_BIGENDIAN
val = bswap16(val);
#endif
return val;
}
void serial_mm_writew (void *opaque,
target_phys_addr_t addr, uint32_t value)
{
SerialState *s = opaque;
#ifdef TARGET_WORDS_BIGENDIAN
value = bswap16(value);
#endif
serial_ioport_write(s, (addr - s->base) >> s->it_shift, value & 0xFFFF);
}
uint32_t serial_mm_readl (void *opaque, target_phys_addr_t addr)
{
SerialState *s = opaque;
uint32_t val;
val = serial_ioport_read(s, (addr - s->base) >> s->it_shift);
#ifdef TARGET_WORDS_BIGENDIAN
val = bswap32(val);
#endif
return val;
}
void serial_mm_writel (void *opaque,
target_phys_addr_t addr, uint32_t value)
{
SerialState *s = opaque;
#ifdef TARGET_WORDS_BIGENDIAN
value = bswap32(value);
#endif
serial_ioport_write(s, (addr - s->base) >> s->it_shift, value);
}
static CPUReadMemoryFunc *serial_mm_read[] = {
&serial_mm_readb,
&serial_mm_readw,
&serial_mm_readl,
};
static CPUWriteMemoryFunc *serial_mm_write[] = {
&serial_mm_writeb,
&serial_mm_writew,
&serial_mm_writel,
};
SerialState *serial_mm_init (target_phys_addr_t base, int it_shift,
qemu_irq irq, CharDriverState *chr,
int ioregister)
{
SerialState *s;
int s_io_memory;
s = qemu_mallocz(sizeof(SerialState));
if (!s)
return NULL;
s->irq = irq;
s->base = base;
s->it_shift = it_shift;
qemu_register_reset(serial_reset, s);
serial_reset(s);
register_savevm("serial", base, 2, serial_save, serial_load, s);
if (ioregister) {
s_io_memory = cpu_register_io_memory(0, serial_mm_read,
serial_mm_write, s);
cpu_register_physical_memory(base, 8 << it_shift, s_io_memory);
}
s->chr = chr;
qemu_chr_add_handlers(chr, serial_can_receive1, serial_receive1,
serial_event, s);
return s;
}
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