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qemu/hw/imx_serial.c
Peter Chubb 40b6f91151 i.MX: UART support 
Implement the Freescale i.MX UART.  This uart is used in a variety of
SoCs, including some by Motorola, as well as in the Freescale i.MX
series.

This patch gives only a `bare-bones' implementation, enough to run Linux
or OKL4, but that's about it.

Signed-off-by: Philip O'Sullivan <philipo@ok-labs.com>
Signed-off-by: Peter Chubb <peter.chubb@nicta.com.au>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2012-07-04 10:43:33 +00:00

468 lines
13 KiB
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/*
* IMX31 UARTS
*
* Copyright (c) 2008 OKL
* Originally Written by Hans Jiang
* Copyright (c) 2011 NICTA Pty Ltd.
*
* This work is licensed under the terms of the GNU GPL, version 2 or later.
* See the COPYING file in the top-level directory.
*
* This is a `bare-bones' implementation of the IMX series serial ports.
* TODO:
* -- implement FIFOs. The real hardware has 32 word transmit
* and receive FIFOs; we currently use a 1-char buffer
* -- implement DMA
* -- implement BAUD-rate and modem lines, for when the backend
* is a real serial device.
*/
#include "hw.h"
#include "sysbus.h"
#include "sysemu.h"
#include "qemu-char.h"
#include "imx.h"
//#define DEBUG_SERIAL 1
#ifdef DEBUG_SERIAL
#define DPRINTF(fmt, args...) \
do { printf("imx_serial: " fmt , ##args); } while (0)
#else
#define DPRINTF(fmt, args...) do {} while (0)
#endif
/*
* Define to 1 for messages about attempts to
* access unimplemented registers or similar.
*/
//#define DEBUG_IMPLEMENTATION 1
#ifdef DEBUG_IMPLEMENTATION
# define IPRINTF(fmt, args...) \
do { fprintf(stderr, "imx_serial: " fmt, ##args); } while (0)
#else
# define IPRINTF(fmt, args...) do {} while (0)
#endif
typedef struct {
SysBusDevice busdev;
MemoryRegion iomem;
int32_t readbuff;
uint32_t usr1;
uint32_t usr2;
uint32_t ucr1;
uint32_t ucr2;
uint32_t uts1;
/*
* The registers below are implemented just so that the
* guest OS sees what it has written
*/
uint32_t onems;
uint32_t ufcr;
uint32_t ubmr;
uint32_t ubrc;
uint32_t ucr3;
qemu_irq irq;
CharDriverState *chr;
} IMXSerialState;
static const VMStateDescription vmstate_imx_serial = {
.name = "imx-serial",
.version_id = 1,
.minimum_version_id = 1,
.minimum_version_id_old = 1,
.fields = (VMStateField[]) {
VMSTATE_INT32(readbuff, IMXSerialState),
VMSTATE_UINT32(usr1, IMXSerialState),
VMSTATE_UINT32(usr2, IMXSerialState),
VMSTATE_UINT32(ucr1, IMXSerialState),
VMSTATE_UINT32(uts1, IMXSerialState),
VMSTATE_UINT32(onems, IMXSerialState),
VMSTATE_UINT32(ufcr, IMXSerialState),
VMSTATE_UINT32(ubmr, IMXSerialState),
VMSTATE_UINT32(ubrc, IMXSerialState),
VMSTATE_UINT32(ucr3, IMXSerialState),
VMSTATE_END_OF_LIST()
},
};
#define URXD_CHARRDY (1<<15) /* character read is valid */
#define URXD_ERR (1<<14) /* Character has error */
#define URXD_BRK (1<<11) /* Break received */
#define USR1_PARTYER (1<<15) /* Parity Error */
#define USR1_RTSS (1<<14) /* RTS pin status */
#define USR1_TRDY (1<<13) /* Tx ready */
#define USR1_RTSD (1<<12) /* RTS delta: pin changed state */
#define USR1_ESCF (1<<11) /* Escape sequence interrupt */
#define USR1_FRAMERR (1<<10) /* Framing error */
#define USR1_RRDY (1<<9) /* receiver ready */
#define USR1_AGTIM (1<<8) /* Aging timer interrupt */
#define USR1_DTRD (1<<7) /* DTR changed */
#define USR1_RXDS (1<<6) /* Receiver is idle */
#define USR1_AIRINT (1<<5) /* Aysnch IR interrupt */
#define USR1_AWAKE (1<<4) /* Falling edge detected on RXd pin */
#define USR2_ADET (1<<15) /* Autobaud complete */
#define USR2_TXFE (1<<14) /* Transmit FIFO empty */
#define USR2_DTRF (1<<13) /* DTR/DSR transition */
#define USR2_IDLE (1<<12) /* UART has been idle for too long */
#define USR2_ACST (1<<11) /* Autobaud counter stopped */
#define USR2_RIDELT (1<<10) /* Ring Indicator delta */
#define USR2_RIIN (1<<9) /* Ring Indicator Input */
#define USR2_IRINT (1<<8) /* Serial Infrared Interrupt */
#define USR2_WAKE (1<<7) /* Start bit detected */
#define USR2_DCDDELT (1<<6) /* Data Carrier Detect delta */
#define USR2_DCDIN (1<<5) /* Data Carrier Detect Input */
#define USR2_RTSF (1<<4) /* RTS transition */
#define USR2_TXDC (1<<3) /* Transmission complete */
#define USR2_BRCD (1<<2) /* Break condition detected */
#define USR2_ORE (1<<1) /* Overrun error */
#define USR2_RDR (1<<0) /* Receive data ready */
#define UCR1_TRDYEN (1<<13) /* Tx Ready Interrupt Enable */
#define UCR1_RRDYEN (1<<9) /* Rx Ready Interrupt Enable */
#define UCR1_TXMPTYEN (1<<6) /* Tx Empty Interrupt Enable */
#define UCR1_UARTEN (1<<0) /* UART Enable */
#define UCR2_TXEN (1<<2) /* Transmitter enable */
#define UCR2_RXEN (1<<1) /* Receiver enable */
#define UCR2_SRST (1<<0) /* Reset complete */
#define UTS1_TXEMPTY (1<<6)
#define UTS1_RXEMPTY (1<<5)
#define UTS1_TXFULL (1<<4)
#define UTS1_RXFULL (1<<3)
static void imx_update(IMXSerialState *s)
{
uint32_t flags;
flags = (s->usr1 & s->ucr1) & (USR1_TRDY|USR1_RRDY);
if (!(s->ucr1 & UCR1_TXMPTYEN)) {
flags &= ~USR1_TRDY;
}
qemu_set_irq(s->irq, !!flags);
}
static void imx_serial_reset(IMXSerialState *s)
{
s->usr1 = USR1_TRDY | USR1_RXDS;
/*
* Fake attachment of a terminal: assert RTS.
*/
s->usr1 |= USR1_RTSS;
s->usr2 = USR2_TXFE | USR2_TXDC | USR2_DCDIN;
s->uts1 = UTS1_RXEMPTY | UTS1_TXEMPTY;
s->ucr1 = 0;
s->ucr2 = UCR2_SRST;
s->ucr3 = 0x700;
s->ubmr = 0;
s->ubrc = 4;
s->readbuff = URXD_ERR;
}
static void imx_serial_reset_at_boot(DeviceState *dev)
{
IMXSerialState *s = container_of(dev, IMXSerialState, busdev.qdev);
imx_serial_reset(s);
/*
* enable the uart on boot, so messages from the linux decompresser
* are visible. On real hardware this is done by the boot rom
* before anything else is loaded.
*/
s->ucr1 = UCR1_UARTEN;
s->ucr2 = UCR2_TXEN;
}
static uint64_t imx_serial_read(void *opaque, target_phys_addr_t offset,
unsigned size)
{
IMXSerialState *s = (IMXSerialState *)opaque;
uint32_t c;
DPRINTF("read(offset=%x)\n", offset >> 2);
switch (offset >> 2) {
case 0x0: /* URXD */
c = s->readbuff;
if (!(s->uts1 & UTS1_RXEMPTY)) {
/* Character is valid */
c |= URXD_CHARRDY;
s->usr1 &= ~USR1_RRDY;
s->usr2 &= ~USR2_RDR;
s->uts1 |= UTS1_RXEMPTY;
imx_update(s);
qemu_chr_accept_input(s->chr);
}
return c;
case 0x20: /* UCR1 */
return s->ucr1;
case 0x21: /* UCR2 */
return s->ucr2;
case 0x25: /* USR1 */
return s->usr1;
case 0x26: /* USR2 */
return s->usr2;
case 0x2A: /* BRM Modulator */
return s->ubmr;
case 0x2B: /* Baud Rate Count */
return s->ubrc;
case 0x2d: /* Test register */
return s->uts1;
case 0x24: /* UFCR */
return s->ufcr;
case 0x2c:
return s->onems;
case 0x22: /* UCR3 */
return s->ucr3;
case 0x23: /* UCR4 */
case 0x29: /* BRM Incremental */
return 0x0; /* TODO */
default:
IPRINTF("imx_serial_read: bad offset: 0x%x\n", (int)offset);
return 0;
}
}
static void imx_serial_write(void *opaque, target_phys_addr_t offset,
uint64_t value, unsigned size)
{
IMXSerialState *s = (IMXSerialState *)opaque;
unsigned char ch;
DPRINTF("write(offset=%x, value = %x) to %s\n",
offset >> 2,
(unsigned int)value, s->chr ? s->chr->label : "NODEV");
switch (offset >> 2) {
case 0x10: /* UTXD */
ch = value;
if (s->ucr2 & UCR2_TXEN) {
if (s->chr) {
qemu_chr_fe_write(s->chr, &ch, 1);
}
s->usr1 &= ~USR1_TRDY;
imx_update(s);
s->usr1 |= USR1_TRDY;
imx_update(s);
}
break;
case 0x20: /* UCR1 */
s->ucr1 = value & 0xffff;
DPRINTF("write(ucr1=%x)\n", (unsigned int)value);
imx_update(s);
break;
case 0x21: /* UCR2 */
/*
* Only a few bits in control register 2 are implemented as yet.
* If it's intended to use a real serial device as a back-end, this
* register will have to be implemented more fully.
*/
if (!(value & UCR2_SRST)) {
imx_serial_reset(s);
imx_update(s);
value |= UCR2_SRST;
}
if (value & UCR2_RXEN) {
if (!(s->ucr2 & UCR2_RXEN)) {
qemu_chr_accept_input(s->chr);
}
}
s->ucr2 = value & 0xffff;
break;
case 0x25: /* USR1 */
value &= USR1_AWAKE | USR1_AIRINT | USR1_DTRD | USR1_AGTIM |
USR1_FRAMERR | USR1_ESCF | USR1_RTSD | USR1_PARTYER;
s->usr1 &= ~value;
break;
case 0x26: /* USR2 */
/*
* Writing 1 to some bits clears them; all other
* values are ignored
*/
value &= USR2_ADET | USR2_DTRF | USR2_IDLE | USR2_ACST |
USR2_RIDELT | USR2_IRINT | USR2_WAKE |
USR2_DCDDELT | USR2_RTSF | USR2_BRCD | USR2_ORE;
s->usr2 &= ~value;
break;
/*
* Linux expects to see what it writes to these registers
* We don't currently alter the baud rate
*/
case 0x29: /* UBIR */
s->ubrc = value & 0xffff;
break;
case 0x2a: /* UBMR */
s->ubmr = value & 0xffff;
break;
case 0x2c: /* One ms reg */
s->onems = value & 0xffff;
break;
case 0x24: /* FIFO control register */
s->ufcr = value & 0xffff;
break;
case 0x22: /* UCR3 */
s->ucr3 = value & 0xffff;
break;
case 0x2d: /* UTS1 */
case 0x23: /* UCR4 */
IPRINTF("Unimplemented Register %x written to\n", offset >> 2);
/* TODO */
break;
default:
IPRINTF("imx_serial_write: Bad offset 0x%x\n", (int)offset);
}
}
static int imx_can_receive(void *opaque)
{
IMXSerialState *s = (IMXSerialState *)opaque;
return !(s->usr1 & USR1_RRDY);
}
static void imx_put_data(void *opaque, uint32_t value)
{
IMXSerialState *s = (IMXSerialState *)opaque;
DPRINTF("received char\n");
s->usr1 |= USR1_RRDY;
s->usr2 |= USR2_RDR;
s->uts1 &= ~UTS1_RXEMPTY;
s->readbuff = value;
imx_update(s);
}
static void imx_receive(void *opaque, const uint8_t *buf, int size)
{
imx_put_data(opaque, *buf);
}
static void imx_event(void *opaque, int event)
{
if (event == CHR_EVENT_BREAK) {
imx_put_data(opaque, URXD_BRK);
}
}
static const struct MemoryRegionOps imx_serial_ops = {
.read = imx_serial_read,
.write = imx_serial_write,
.endianness = DEVICE_NATIVE_ENDIAN,
};
static int imx_serial_init(SysBusDevice *dev)
{
IMXSerialState *s = FROM_SYSBUS(IMXSerialState, dev);
memory_region_init_io(&s->iomem, &imx_serial_ops, s, "imx-serial", 0x1000);
sysbus_init_mmio(dev, &s->iomem);
sysbus_init_irq(dev, &s->irq);
if (s->chr) {
qemu_chr_add_handlers(s->chr, imx_can_receive, imx_receive,
imx_event, s);
} else {
DPRINTF("No char dev for uart at 0x%lx\n",
(unsigned long)s->iomem.ram_addr);
}
return 0;
}
void imx_serial_create(int uart, const target_phys_addr_t addr, qemu_irq irq)
{
DeviceState *dev;
SysBusDevice *bus;
CharDriverState *chr;
const char chr_name[] = "serial";
char label[ARRAY_SIZE(chr_name) + 1];
dev = qdev_create(NULL, "imx-serial");
if (uart >= MAX_SERIAL_PORTS) {
hw_error("Cannot assign uart %d: QEMU supports only %d ports\n",
uart, MAX_SERIAL_PORTS);
}
chr = serial_hds[uart];
if (!chr) {
snprintf(label, ARRAY_SIZE(label), "%s%d", chr_name, uart);
chr = qemu_chr_new(label, "null", NULL);
if (!(chr)) {
hw_error("Can't assign serial port to imx-uart%d.\n", uart);
}
}
qdev_prop_set_chr(dev, "chardev", chr);
bus = sysbus_from_qdev(dev);
qdev_init_nofail(dev);
if (addr != (target_phys_addr_t)-1) {
sysbus_mmio_map(bus, 0, addr);
}
sysbus_connect_irq(bus, 0, irq);
}
static Property imx32_serial_properties[] = {
DEFINE_PROP_CHR("chardev", IMXSerialState, chr),
DEFINE_PROP_END_OF_LIST(),
};
static void imx_serial_class_init(ObjectClass *klass, void *data)
{
DeviceClass *dc = DEVICE_CLASS(klass);
SysBusDeviceClass *k = SYS_BUS_DEVICE_CLASS(klass);
k->init = imx_serial_init;
dc->vmsd = &vmstate_imx_serial;
dc->reset = imx_serial_reset_at_boot;
dc->desc = "i.MX series UART";
dc->props = imx32_serial_properties;
}
static TypeInfo imx_serial_info = {
.name = "imx-serial",
.parent = TYPE_SYS_BUS_DEVICE,
.instance_size = sizeof(IMXSerialState),
.class_init = imx_serial_class_init,
};
static void imx_serial_register_types(void)
{
type_register_static(&imx_serial_info);
}
type_init(imx_serial_register_types)
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