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qemu/hw/char/imx_serial.c
Hans-Erik Floryd 3c54cf7705 imx_serial: Generate interrupt on receive data ready if enabled 
Generate an interrupt if USR2_RDR and UCR4_DREN are both set.

Signed-off-by: Hans-Erik Floryd <hans-erik.floryd@rt-labs.com>
Message-id: 1534341354-11956-1-git-send-email-hans-erik.floryd@rt-labs.com
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2018-08-20 11:24:31 +01:00

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/*
* IMX31 UARTS
*
* Copyright (c) 2008 OKL
* Originally Written by Hans Jiang
* Copyright (c) 2011 NICTA Pty Ltd.
* Updated by Jean-Christophe Dubois <jcd@tribudubois.net>
*
* 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 "qemu/osdep.h"
#include "hw/char/imx_serial.h"
#include "sysemu/sysemu.h"
#include "qemu/log.h"
#ifndef DEBUG_IMX_UART
#define DEBUG_IMX_UART 0
#endif
#define DPRINTF(fmt, args...) \
do { \
if (DEBUG_IMX_UART) { \
fprintf(stderr, "[%s]%s: " fmt , TYPE_IMX_SERIAL, \
__func__, ##args); \
} \
} while (0)
static const VMStateDescription vmstate_imx_serial = {
.name = TYPE_IMX_SERIAL,
.version_id = 2,
.minimum_version_id = 2,
.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_UINT32(ucr4, IMXSerialState),
VMSTATE_END_OF_LIST()
},
};
static void imx_update(IMXSerialState *s)
{
uint32_t usr1;
uint32_t usr2;
uint32_t mask;
/*
* Lucky for us TRDY and RRDY has the same offset in both USR1 and
* UCR1, so we can get away with something as simple as the
* following:
*/
usr1 = s->usr1 & s->ucr1 & (USR1_TRDY | USR1_RRDY);
/*
* Bits that we want in USR2 are not as conveniently laid out,
* unfortunately.
*/
mask = (s->ucr1 & UCR1_TXMPTYEN) ? USR2_TXFE : 0;
/*
* TCEN and TXDC are both bit 3
* RDR and DREN are both bit 0
*/
mask |= s->ucr4 & (UCR4_TCEN | UCR4_DREN);
usr2 = s->usr2 & mask;
qemu_set_irq(s->irq, usr1 || usr2);
}
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 = IMX_SERIAL(dev);
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, hwaddr offset,
unsigned size)
{
IMXSerialState *s = (IMXSerialState *)opaque;
uint32_t c;
DPRINTF("read(offset=0x%" HWADDR_PRIx ")\n", offset);
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_fe_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 */
return s->ucr4;
case 0x29: /* BRM Incremental */
return 0x0; /* TODO */
default:
qemu_log_mask(LOG_GUEST_ERROR, "[%s]%s: Bad register at offset 0x%"
HWADDR_PRIx "\n", TYPE_IMX_SERIAL, __func__, offset);
return 0;
}
}
static void imx_serial_write(void *opaque, hwaddr offset,
uint64_t value, unsigned size)
{
IMXSerialState *s = (IMXSerialState *)opaque;
Chardev *chr = qemu_chr_fe_get_driver(&s->chr);
unsigned char ch;
DPRINTF("write(offset=0x%" HWADDR_PRIx ", value = 0x%x) to %s\n",
offset, (unsigned int)value, chr ? chr->label : "NODEV");
switch (offset >> 2) {
case 0x10: /* UTXD */
ch = value;
if (s->ucr2 & UCR2_TXEN) {
/* 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);
s->usr1 &= ~USR1_TRDY;
s->usr2 &= ~USR2_TXDC;
imx_update(s);
s->usr1 |= USR1_TRDY;
s->usr2 |= USR2_TXDC;
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_fe_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 0x23: /* UCR4 */
s->ucr4 = value & 0xffff;
imx_update(s);
break;
case 0x2d: /* UTS1 */
qemu_log_mask(LOG_UNIMP, "[%s]%s: Unimplemented reg 0x%"
HWADDR_PRIx "\n", TYPE_IMX_SERIAL, __func__, offset);
/* TODO */
break;
default:
qemu_log_mask(LOG_GUEST_ERROR, "[%s]%s: Bad register at offset 0x%"
HWADDR_PRIx "\n", TYPE_IMX_SERIAL, __func__, 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;
if (value & URXD_BRK) {
s->usr2 |= USR2_BRCD;
}
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 | URXD_FRMERR | URXD_ERR);
}
}
static const struct MemoryRegionOps imx_serial_ops = {
.read = imx_serial_read,
.write = imx_serial_write,
.endianness = DEVICE_NATIVE_ENDIAN,
};
static void imx_serial_realize(DeviceState *dev, Error **errp)
{
IMXSerialState *s = IMX_SERIAL(dev);
DPRINTF("char dev for uart: %p\n", qemu_chr_fe_get_driver(&s->chr));
qemu_chr_fe_set_handlers(&s->chr, imx_can_receive, imx_receive,
imx_event, NULL, s, NULL, true);
}
static void imx_serial_init(Object *obj)
{
SysBusDevice *sbd = SYS_BUS_DEVICE(obj);
IMXSerialState *s = IMX_SERIAL(obj);
memory_region_init_io(&s->iomem, obj, &imx_serial_ops, s,
TYPE_IMX_SERIAL, 0x1000);
sysbus_init_mmio(sbd, &s->iomem);
sysbus_init_irq(sbd, &s->irq);
}
static Property imx_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);
dc->realize = imx_serial_realize;
dc->vmsd = &vmstate_imx_serial;
dc->reset = imx_serial_reset_at_boot;
set_bit(DEVICE_CATEGORY_INPUT, dc->categories);
dc->desc = "i.MX series UART";
dc->props = imx_serial_properties;
}
static const TypeInfo imx_serial_info = {
.name = TYPE_IMX_SERIAL,
.parent = TYPE_SYS_BUS_DEVICE,
.instance_size = sizeof(IMXSerialState),
.instance_init = imx_serial_init,
.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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