hw/char/sifive_uart.c - qemu - Git at Google

 /*
  * QEMU model of the UART on the SiFive E300 and U500 series SOCs.
  *
  * Copyright (c) 2016 Stefan O'Rear
  *
  * This program is free software; you can redistribute it and/or modify it
  * under the terms and conditions of the GNU General Public License,
  * version 2 or later, as published by the Free Software Foundation.
  *
  * This program is distributed in the hope it will be useful, but WITHOUT
  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  * more details.
  *
  * You should have received a copy of the GNU General Public License along with
  * this program.  If not, see <http://www.gnu.org/licenses/>.
  */

 #include "qemu/osdep.h"
 #include "qapi/error.h"
 #include "qemu/log.h"
 #include "migration/vmstate.h"
 #include "chardev/char.h"
 #include "chardev/char-fe.h"
 #include "hw/irq.h"
 #include "hw/char/sifive_uart.h"
 #include "hw/qdev-properties-system.h"

 #define TX_INTERRUPT_TRIGGER_DELAY_NS 100

 /*
  * Not yet implemented:
  *
  * Transmit FIFO using "qemu/fifo8.h"
  */

 /* Returns the state of the IP (interrupt pending) register */
 static uint64_t sifive_uart_ip(SiFiveUARTState *s)
 {
     uint64_t ret = 0;

     uint64_t txcnt = SIFIVE_UART_GET_TXCNT(s->txctrl);
     uint64_t rxcnt = SIFIVE_UART_GET_RXCNT(s->rxctrl);

     if (txcnt != 0) {
         ret |= SIFIVE_UART_IP_TXWM;
     }
     if (s->rx_fifo_len > rxcnt) {
         ret |= SIFIVE_UART_IP_RXWM;
     }

     return ret;
 }

 static void sifive_uart_update_irq(SiFiveUARTState *s)
 {
     int cond = 0;
     if ((s->ie & SIFIVE_UART_IE_TXWM) ||
         ((s->ie & SIFIVE_UART_IE_RXWM) && s->rx_fifo_len)) {
         cond = 1;
     }
     if (cond) {
         qemu_irq_raise(s->irq);
     } else {
         qemu_irq_lower(s->irq);
     }
 }

 static gboolean sifive_uart_xmit(void *do_not_use, GIOCondition cond,
                                  void *opaque)
 {
     SiFiveUARTState *s = opaque;
     int ret;
     const uint8_t *characters;
     uint32_t numptr = 0;

     /* instant drain the fifo when there's no back-end */
     if (!qemu_chr_fe_backend_connected(&s->chr)) {
         fifo8_reset(&s->tx_fifo);
         return G_SOURCE_REMOVE;
     }

     if (fifo8_is_empty(&s->tx_fifo)) {
         return G_SOURCE_REMOVE;
     }

     /* Don't pop the FIFO in case the write fails */
     characters = fifo8_peek_bufptr(&s->tx_fifo,
                                    fifo8_num_used(&s->tx_fifo), &numptr);
     ret = qemu_chr_fe_write(&s->chr, characters, numptr);

     if (ret >= 0) {
         /* We wrote the data, actually pop the fifo */
         fifo8_pop_bufptr(&s->tx_fifo, ret, NULL);
     }

     if (!fifo8_is_empty(&s->tx_fifo)) {
         guint r = qemu_chr_fe_add_watch(&s->chr, G_IO_OUT | G_IO_HUP,
                                         sifive_uart_xmit, s);
         if (!r) {
             fifo8_reset(&s->tx_fifo);
             return G_SOURCE_REMOVE;
         }
     }

     /* Clear the TX Full bit */
     if (!fifo8_is_full(&s->tx_fifo)) {
         s->txfifo &= ~SIFIVE_UART_TXFIFO_FULL;
     }

     sifive_uart_update_irq(s);
     return G_SOURCE_REMOVE;
 }

 static void sifive_uart_write_tx_fifo(SiFiveUARTState *s, const uint8_t *buf,
                                       int size)
 {
     uint64_t current_time = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);

     if (size > fifo8_num_free(&s->tx_fifo)) {
         size = fifo8_num_free(&s->tx_fifo);
         qemu_log_mask(LOG_GUEST_ERROR, "sifive_uart: TX FIFO overflow");
     }

     fifo8_push_all(&s->tx_fifo, buf, size);

     if (fifo8_is_full(&s->tx_fifo)) {
         s->txfifo |= SIFIVE_UART_TXFIFO_FULL;
     }

     timer_mod(s->fifo_trigger_handle, current_time +
                   TX_INTERRUPT_TRIGGER_DELAY_NS);
 }

 static uint64_t
 sifive_uart_read(void *opaque, hwaddr addr, unsigned int size)
 {
     SiFiveUARTState *s = opaque;
     unsigned char r;
     switch (addr) {
     case SIFIVE_UART_RXFIFO:
         if (s->rx_fifo_len) {
             r = s->rx_fifo[0];
             memmove(s->rx_fifo, s->rx_fifo + 1, s->rx_fifo_len - 1);
             s->rx_fifo_len--;
             qemu_chr_fe_accept_input(&s->chr);
             sifive_uart_update_irq(s);
             return r;
         }
         return 0x80000000;

     case SIFIVE_UART_TXFIFO:
         return s->txfifo;
     case SIFIVE_UART_IE:
         return s->ie;
     case SIFIVE_UART_IP:
         return sifive_uart_ip(s);
     case SIFIVE_UART_TXCTRL:
         return s->txctrl;
     case SIFIVE_UART_RXCTRL:
         return s->rxctrl;
     case SIFIVE_UART_DIV:
         return s->div;
     }

     qemu_log_mask(LOG_GUEST_ERROR, "%s: bad read: addr=0x%x\n",
                   __func__, (int)addr);
     return 0;
 }

 static void
 sifive_uart_write(void *opaque, hwaddr addr,
                   uint64_t val64, unsigned int size)
 {
     SiFiveUARTState *s = opaque;
     uint32_t value = val64;
     uint8_t ch = value;

     switch (addr) {
     case SIFIVE_UART_TXFIFO:
         sifive_uart_write_tx_fifo(s, &ch, 1);
         return;
     case SIFIVE_UART_IE:
         s->ie = val64;
         sifive_uart_update_irq(s);
         return;
     case SIFIVE_UART_TXCTRL:
         s->txctrl = val64;
         return;
     case SIFIVE_UART_RXCTRL:
         s->rxctrl = val64;
         return;
     case SIFIVE_UART_DIV:
         s->div = val64;
         return;
     }
     qemu_log_mask(LOG_GUEST_ERROR, "%s: bad write: addr=0x%x v=0x%x\n",
                   __func__, (int)addr, (int)value);
 }

 static void fifo_trigger_update(void *opaque)
 {
     SiFiveUARTState *s = opaque;

     sifive_uart_xmit(NULL, G_IO_OUT, s);
 }

 static const MemoryRegionOps sifive_uart_ops = {
     .read = sifive_uart_read,
     .write = sifive_uart_write,
     .endianness = DEVICE_NATIVE_ENDIAN,
     .valid = {
         .min_access_size = 4,
         .max_access_size = 4
     }
 };

 static void sifive_uart_rx(void *opaque, const uint8_t *buf, int size)
 {
     SiFiveUARTState *s = opaque;

     /* Got a byte.  */
     if (s->rx_fifo_len >= sizeof(s->rx_fifo)) {
         printf("WARNING: UART dropped char.\n");
         return;
     }
     s->rx_fifo[s->rx_fifo_len++] = *buf;

     sifive_uart_update_irq(s);
 }

 static int sifive_uart_can_rx(void *opaque)
 {
     SiFiveUARTState *s = opaque;

     return s->rx_fifo_len < sizeof(s->rx_fifo);
 }

 static void sifive_uart_event(void *opaque, QEMUChrEvent event)
 {
 }

 static int sifive_uart_be_change(void *opaque)
 {
     SiFiveUARTState *s = opaque;

     qemu_chr_fe_set_handlers(&s->chr, sifive_uart_can_rx, sifive_uart_rx,
                              sifive_uart_event, sifive_uart_be_change, s,
                              NULL, true);

     return 0;
 }

 static const Property sifive_uart_properties[] = {
     DEFINE_PROP_CHR("chardev", SiFiveUARTState, chr),
 };

 static void sifive_uart_init(Object *obj)
 {
     SysBusDevice *sbd = SYS_BUS_DEVICE(obj);
     SiFiveUARTState *s = SIFIVE_UART(obj);

     memory_region_init_io(&s->mmio, OBJECT(s), &sifive_uart_ops, s,
                           TYPE_SIFIVE_UART, SIFIVE_UART_MAX);
     sysbus_init_mmio(sbd, &s->mmio);
     sysbus_init_irq(sbd, &s->irq);
 }

 static void sifive_uart_realize(DeviceState *dev, Error **errp)
 {
     SiFiveUARTState *s = SIFIVE_UART(dev);

     s->fifo_trigger_handle = timer_new_ns(QEMU_CLOCK_VIRTUAL,
                                           fifo_trigger_update, s);

     qemu_chr_fe_set_handlers(&s->chr, sifive_uart_can_rx, sifive_uart_rx,
                              sifive_uart_event, sifive_uart_be_change, s,
                              NULL, true);

 }

 static void sifive_uart_reset_enter(Object *obj, ResetType type)
 {
     SiFiveUARTState *s = SIFIVE_UART(obj);

     s->txfifo = 0;
     s->ie = 0;
     s->ip = 0;
     s->txctrl = 0;
     s->rxctrl = 0;
     s->div = 0;

     s->rx_fifo_len = 0;

     memset(s->rx_fifo, 0, SIFIVE_UART_RX_FIFO_SIZE);
     fifo8_create(&s->tx_fifo, SIFIVE_UART_TX_FIFO_SIZE);
 }

 static void sifive_uart_reset_hold(Object *obj, ResetType type)
 {
     SiFiveUARTState *s = SIFIVE_UART(obj);
     qemu_irq_lower(s->irq);
 }

 static const VMStateDescription vmstate_sifive_uart = {
     .name = TYPE_SIFIVE_UART,
     .version_id = 2,
     .minimum_version_id = 2,
     .fields = (const VMStateField[]) {
         VMSTATE_UINT8_ARRAY(rx_fifo, SiFiveUARTState,
                             SIFIVE_UART_RX_FIFO_SIZE),
         VMSTATE_UINT8(rx_fifo_len, SiFiveUARTState),
         VMSTATE_UINT32(ie, SiFiveUARTState),
         VMSTATE_UINT32(ip, SiFiveUARTState),
         VMSTATE_UINT32(txctrl, SiFiveUARTState),
         VMSTATE_UINT32(rxctrl, SiFiveUARTState),
         VMSTATE_UINT32(div, SiFiveUARTState),
         VMSTATE_UINT32(txfifo, SiFiveUARTState),
         VMSTATE_FIFO8(tx_fifo, SiFiveUARTState),
         VMSTATE_TIMER_PTR(fifo_trigger_handle, SiFiveUARTState),
         VMSTATE_END_OF_LIST()
     },
 };


 static void sifive_uart_class_init(ObjectClass *oc, void *data)
 {
     DeviceClass *dc = DEVICE_CLASS(oc);
     ResettableClass *rc = RESETTABLE_CLASS(oc);

     dc->realize = sifive_uart_realize;
     dc->vmsd = &vmstate_sifive_uart;
     rc->phases.enter = sifive_uart_reset_enter;
     rc->phases.hold  = sifive_uart_reset_hold;
     device_class_set_props(dc, sifive_uart_properties);
     set_bit(DEVICE_CATEGORY_INPUT, dc->categories);
 }

 static const TypeInfo sifive_uart_info = {
     .name          = TYPE_SIFIVE_UART,
     .parent        = TYPE_SYS_BUS_DEVICE,
     .instance_size = sizeof(SiFiveUARTState),
     .instance_init = sifive_uart_init,
     .class_init    = sifive_uart_class_init,
 };

 static void sifive_uart_register_types(void)
 {
     type_register_static(&sifive_uart_info);
 }

 type_init(sifive_uart_register_types)

 /*
  * Create UART device.
  */
 SiFiveUARTState *sifive_uart_create(MemoryRegion *address_space, hwaddr base,
     Chardev *chr, qemu_irq irq)
 {
     DeviceState *dev;
     SysBusDevice *s;

     dev = qdev_new("riscv.sifive.uart");
     s = SYS_BUS_DEVICE(dev);
     qdev_prop_set_chr(dev, "chardev", chr);
     sysbus_realize_and_unref(s, &error_fatal);
     memory_region_add_subregion(address_space, base,
                                 sysbus_mmio_get_region(s, 0));
     sysbus_connect_irq(s, 0, irq);

     return SIFIVE_UART(dev);
 }
	/*
	* QEMU model of the UART on the SiFive E300 and U500 series SOCs.
	*
	* Copyright (c) 2016 Stefan O'Rear
	*
	* This program is free software; you can redistribute it and/or modify it
	* under the terms and conditions of the GNU General Public License,
	* version 2 or later, as published by the Free Software Foundation.
	*
	* This program is distributed in the hope it will be useful, but WITHOUT
	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
	* more details.
	*
	* You should have received a copy of the GNU General Public License along with
	* this program. If not, see <http://www.gnu.org/licenses/>.
	*/

	#include "qemu/osdep.h"
	#include "qapi/error.h"
	#include "qemu/log.h"
	#include "migration/vmstate.h"
	#include "chardev/char.h"
	#include "chardev/char-fe.h"
	#include "hw/irq.h"
	#include "hw/char/sifive_uart.h"
	#include "hw/qdev-properties-system.h"

	#define TX_INTERRUPT_TRIGGER_DELAY_NS 100

	/*
	* Not yet implemented:
	*
	* Transmit FIFO using "qemu/fifo8.h"
	*/

	/* Returns the state of the IP (interrupt pending) register */
	static uint64_t sifive_uart_ip(SiFiveUARTState *s)
	{
	uint64_t ret = 0;

	uint64_t txcnt = SIFIVE_UART_GET_TXCNT(s->txctrl);
	uint64_t rxcnt = SIFIVE_UART_GET_RXCNT(s->rxctrl);

	if (txcnt != 0) {
	ret \|= SIFIVE_UART_IP_TXWM;
	}
	if (s->rx_fifo_len > rxcnt) {
	ret \|= SIFIVE_UART_IP_RXWM;
	}

	return ret;
	}

	static void sifive_uart_update_irq(SiFiveUARTState *s)
	{
	int cond = 0;
	if ((s->ie & SIFIVE_UART_IE_TXWM) \|\|
	((s->ie & SIFIVE_UART_IE_RXWM) && s->rx_fifo_len)) {
	cond = 1;
	}
	if (cond) {
	qemu_irq_raise(s->irq);
	} else {
	qemu_irq_lower(s->irq);
	}
	}

	static gboolean sifive_uart_xmit(void *do_not_use, GIOCondition cond,
	void *opaque)
	{
	SiFiveUARTState *s = opaque;
	int ret;
	const uint8_t *characters;
	uint32_t numptr = 0;

	/* instant drain the fifo when there's no back-end */
	if (!qemu_chr_fe_backend_connected(&s->chr)) {
	fifo8_reset(&s->tx_fifo);
	return G_SOURCE_REMOVE;
	}

	if (fifo8_is_empty(&s->tx_fifo)) {
	return G_SOURCE_REMOVE;
	}

	/* Don't pop the FIFO in case the write fails */
	characters = fifo8_peek_bufptr(&s->tx_fifo,
	fifo8_num_used(&s->tx_fifo), &numptr);
	ret = qemu_chr_fe_write(&s->chr, characters, numptr);

	if (ret >= 0) {
	/* We wrote the data, actually pop the fifo */
	fifo8_pop_bufptr(&s->tx_fifo, ret, NULL);
	}

	if (!fifo8_is_empty(&s->tx_fifo)) {
	guint r = qemu_chr_fe_add_watch(&s->chr, G_IO_OUT \| G_IO_HUP,
	sifive_uart_xmit, s);
	if (!r) {
	fifo8_reset(&s->tx_fifo);
	return G_SOURCE_REMOVE;
	}
	}

	/* Clear the TX Full bit */
	if (!fifo8_is_full(&s->tx_fifo)) {
	s->txfifo &= ~SIFIVE_UART_TXFIFO_FULL;
	}

	sifive_uart_update_irq(s);
	return G_SOURCE_REMOVE;
	}

	static void sifive_uart_write_tx_fifo(SiFiveUARTState s, const uint8_t buf,
	int size)
	{
	uint64_t current_time = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);

	if (size > fifo8_num_free(&s->tx_fifo)) {
	size = fifo8_num_free(&s->tx_fifo);
	qemu_log_mask(LOG_GUEST_ERROR, "sifive_uart: TX FIFO overflow");
	}

	fifo8_push_all(&s->tx_fifo, buf, size);

	if (fifo8_is_full(&s->tx_fifo)) {
	s->txfifo \|= SIFIVE_UART_TXFIFO_FULL;
	}

	timer_mod(s->fifo_trigger_handle, current_time +
	TX_INTERRUPT_TRIGGER_DELAY_NS);
	}

	static uint64_t
	sifive_uart_read(void *opaque, hwaddr addr, unsigned int size)
	{
	SiFiveUARTState *s = opaque;
	unsigned char r;
	switch (addr) {
	case SIFIVE_UART_RXFIFO:
	if (s->rx_fifo_len) {
	r = s->rx_fifo[0];
	memmove(s->rx_fifo, s->rx_fifo + 1, s->rx_fifo_len - 1);
	s->rx_fifo_len--;
	qemu_chr_fe_accept_input(&s->chr);
	sifive_uart_update_irq(s);
	return r;
	}
	return 0x80000000;

	case SIFIVE_UART_TXFIFO:
	return s->txfifo;
	case SIFIVE_UART_IE:
	return s->ie;
	case SIFIVE_UART_IP:
	return sifive_uart_ip(s);
	case SIFIVE_UART_TXCTRL:
	return s->txctrl;
	case SIFIVE_UART_RXCTRL:
	return s->rxctrl;
	case SIFIVE_UART_DIV:
	return s->div;
	}

	qemu_log_mask(LOG_GUEST_ERROR, "%s: bad read: addr=0x%x\n",
	__func__, (int)addr);
	return 0;
	}

	static void
	sifive_uart_write(void *opaque, hwaddr addr,
	uint64_t val64, unsigned int size)
	{
	SiFiveUARTState *s = opaque;
	uint32_t value = val64;
	uint8_t ch = value;

	switch (addr) {
	case SIFIVE_UART_TXFIFO:
	sifive_uart_write_tx_fifo(s, &ch, 1);
	return;
	case SIFIVE_UART_IE:
	s->ie = val64;
	sifive_uart_update_irq(s);
	return;
	case SIFIVE_UART_TXCTRL:
	s->txctrl = val64;
	return;
	case SIFIVE_UART_RXCTRL:
	s->rxctrl = val64;
	return;
	case SIFIVE_UART_DIV:
	s->div = val64;
	return;
	}
	qemu_log_mask(LOG_GUEST_ERROR, "%s: bad write: addr=0x%x v=0x%x\n",
	__func__, (int)addr, (int)value);
	}

	static void fifo_trigger_update(void *opaque)
	{
	SiFiveUARTState *s = opaque;

	sifive_uart_xmit(NULL, G_IO_OUT, s);
	}

	static const MemoryRegionOps sifive_uart_ops = {
	.read = sifive_uart_read,
	.write = sifive_uart_write,
	.endianness = DEVICE_NATIVE_ENDIAN,
	.valid = {
	.min_access_size = 4,
	.max_access_size = 4
	}
	};

	static void sifive_uart_rx(void opaque, const uint8_t buf, int size)
	{
	SiFiveUARTState *s = opaque;

	/* Got a byte. */
	if (s->rx_fifo_len >= sizeof(s->rx_fifo)) {
	printf("WARNING: UART dropped char.\n");
	return;
	}
	s->rx_fifo[s->rx_fifo_len++] = *buf;

	sifive_uart_update_irq(s);
	}

	static int sifive_uart_can_rx(void *opaque)
	{
	SiFiveUARTState *s = opaque;

	return s->rx_fifo_len < sizeof(s->rx_fifo);
	}

	static void sifive_uart_event(void *opaque, QEMUChrEvent event)
	{
	}

	static int sifive_uart_be_change(void *opaque)
	{
	SiFiveUARTState *s = opaque;

	qemu_chr_fe_set_handlers(&s->chr, sifive_uart_can_rx, sifive_uart_rx,
	sifive_uart_event, sifive_uart_be_change, s,
	NULL, true);

	return 0;
	}

	static const Property sifive_uart_properties[] = {
	DEFINE_PROP_CHR("chardev", SiFiveUARTState, chr),
	};

	static void sifive_uart_init(Object *obj)
	{
	SysBusDevice *sbd = SYS_BUS_DEVICE(obj);
	SiFiveUARTState *s = SIFIVE_UART(obj);

	memory_region_init_io(&s->mmio, OBJECT(s), &sifive_uart_ops, s,
	TYPE_SIFIVE_UART, SIFIVE_UART_MAX);
	sysbus_init_mmio(sbd, &s->mmio);
	sysbus_init_irq(sbd, &s->irq);
	}

	static void sifive_uart_realize(DeviceState dev, Error *errp)
	{
	SiFiveUARTState *s = SIFIVE_UART(dev);

	s->fifo_trigger_handle = timer_new_ns(QEMU_CLOCK_VIRTUAL,
	fifo_trigger_update, s);

	qemu_chr_fe_set_handlers(&s->chr, sifive_uart_can_rx, sifive_uart_rx,
	sifive_uart_event, sifive_uart_be_change, s,
	NULL, true);

	}

	static void sifive_uart_reset_enter(Object *obj, ResetType type)
	{
	SiFiveUARTState *s = SIFIVE_UART(obj);

	s->txfifo = 0;
	s->ie = 0;
	s->ip = 0;
	s->txctrl = 0;
	s->rxctrl = 0;
	s->div = 0;

	s->rx_fifo_len = 0;

	memset(s->rx_fifo, 0, SIFIVE_UART_RX_FIFO_SIZE);
	fifo8_create(&s->tx_fifo, SIFIVE_UART_TX_FIFO_SIZE);
	}

	static void sifive_uart_reset_hold(Object *obj, ResetType type)
	{
	SiFiveUARTState *s = SIFIVE_UART(obj);
	qemu_irq_lower(s->irq);
	}

	static const VMStateDescription vmstate_sifive_uart = {
	.name = TYPE_SIFIVE_UART,
	.version_id = 2,
	.minimum_version_id = 2,
	.fields = (const VMStateField[]) {
	VMSTATE_UINT8_ARRAY(rx_fifo, SiFiveUARTState,
	SIFIVE_UART_RX_FIFO_SIZE),
	VMSTATE_UINT8(rx_fifo_len, SiFiveUARTState),
	VMSTATE_UINT32(ie, SiFiveUARTState),
	VMSTATE_UINT32(ip, SiFiveUARTState),
	VMSTATE_UINT32(txctrl, SiFiveUARTState),
	VMSTATE_UINT32(rxctrl, SiFiveUARTState),
	VMSTATE_UINT32(div, SiFiveUARTState),
	VMSTATE_UINT32(txfifo, SiFiveUARTState),
	VMSTATE_FIFO8(tx_fifo, SiFiveUARTState),
	VMSTATE_TIMER_PTR(fifo_trigger_handle, SiFiveUARTState),
	VMSTATE_END_OF_LIST()
	},
	};


	static void sifive_uart_class_init(ObjectClass oc, void data)
	{
	DeviceClass *dc = DEVICE_CLASS(oc);
	ResettableClass *rc = RESETTABLE_CLASS(oc);

	dc->realize = sifive_uart_realize;
	dc->vmsd = &vmstate_sifive_uart;
	rc->phases.enter = sifive_uart_reset_enter;
	rc->phases.hold = sifive_uart_reset_hold;
	device_class_set_props(dc, sifive_uart_properties);
	set_bit(DEVICE_CATEGORY_INPUT, dc->categories);
	}

	static const TypeInfo sifive_uart_info = {
	.name = TYPE_SIFIVE_UART,
	.parent = TYPE_SYS_BUS_DEVICE,
	.instance_size = sizeof(SiFiveUARTState),
	.instance_init = sifive_uart_init,
	.class_init = sifive_uart_class_init,
	};

	static void sifive_uart_register_types(void)
	{
	type_register_static(&sifive_uart_info);
	}

	type_init(sifive_uart_register_types)

	/*
	* Create UART device.
	*/
	SiFiveUARTState sifive_uart_create(MemoryRegion address_space, hwaddr base,
	Chardev *chr, qemu_irq irq)
	{
	DeviceState *dev;
	SysBusDevice *s;

	dev = qdev_new("riscv.sifive.uart");
	s = SYS_BUS_DEVICE(dev);
	qdev_prop_set_chr(dev, "chardev", chr);
	sysbus_realize_and_unref(s, &error_fatal);
	memory_region_add_subregion(address_space, base,
	sysbus_mmio_get_region(s, 0));
	sysbus_connect_irq(s, 0, irq);

	return SIFIVE_UART(dev);
	}