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-rw-r--r--MAINTAINERS2
-rw-r--r--hw/char/Kconfig3
-rw-r--r--hw/char/Makefile.objs1
-rw-r--r--hw/char/avr_usart.c320
-rw-r--r--include/hw/char/avr_usart.h93
5 files changed, 419 insertions, 0 deletions
diff --git a/MAINTAINERS b/MAINTAINERS
index 659a9c789f..be903053de 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -983,6 +983,8 @@ M: Michael Rolnik <mrolnik@gmail.com>
R: Sarah Harris <S.E.Harris@kent.ac.uk>
S: Maintained
F: default-configs/avr-softmmu.mak
+F: include/hw/char/avr_usart.h
+F: hw/char/avr_usart.c
CRIS Machines
-------------
diff --git a/hw/char/Kconfig b/hw/char/Kconfig
index 874627520c..b7e0e4d5fa 100644
--- a/hw/char/Kconfig
+++ b/hw/char/Kconfig
@@ -49,3 +49,6 @@ config TERMINAL3270
config RENESAS_SCI
bool
+
+config AVR_USART
+ bool
diff --git a/hw/char/Makefile.objs b/hw/char/Makefile.objs
index 8306c4a789..bf177ac41d 100644
--- a/hw/char/Makefile.objs
+++ b/hw/char/Makefile.objs
@@ -22,6 +22,7 @@ common-obj-$(CONFIG_DIGIC) += digic-uart.o
common-obj-$(CONFIG_STM32F2XX_USART) += stm32f2xx_usart.o
common-obj-$(CONFIG_RASPI) += bcm2835_aux.o
common-obj-$(CONFIG_RENESAS_SCI) += renesas_sci.o
+common-obj-$(CONFIG_AVR_USART) += avr_usart.o
common-obj-$(CONFIG_CMSDK_APB_UART) += cmsdk-apb-uart.o
common-obj-$(CONFIG_ETRAXFS) += etraxfs_ser.o
diff --git a/hw/char/avr_usart.c b/hw/char/avr_usart.c
new file mode 100644
index 0000000000..fbe2a112b7
--- /dev/null
+++ b/hw/char/avr_usart.c
@@ -0,0 +1,320 @@
+/*
+ * AVR USART
+ *
+ * Copyright (c) 2018 University of Kent
+ * Author: Sarah Harris
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, see
+ * <http://www.gnu.org/licenses/lgpl-2.1.html>
+ */
+
+#include "qemu/osdep.h"
+#include "hw/char/avr_usart.h"
+#include "qemu/log.h"
+#include "hw/irq.h"
+#include "hw/qdev-properties.h"
+
+static int avr_usart_can_receive(void *opaque)
+{
+ AVRUsartState *usart = opaque;
+
+ if (usart->data_valid || !(usart->csrb & USART_CSRB_RXEN)) {
+ return 0;
+ }
+ return 1;
+}
+
+static void avr_usart_receive(void *opaque, const uint8_t *buffer, int size)
+{
+ AVRUsartState *usart = opaque;
+ assert(size == 1);
+ assert(!usart->data_valid);
+ usart->data = buffer[0];
+ usart->data_valid = true;
+ usart->csra |= USART_CSRA_RXC;
+ if (usart->csrb & USART_CSRB_RXCIE) {
+ qemu_set_irq(usart->rxc_irq, 1);
+ }
+}
+
+static void update_char_mask(AVRUsartState *usart)
+{
+ uint8_t mode = ((usart->csrc & USART_CSRC_CSZ0) ? 1 : 0) |
+ ((usart->csrc & USART_CSRC_CSZ1) ? 2 : 0) |
+ ((usart->csrb & USART_CSRB_CSZ2) ? 4 : 0);
+ switch (mode) {
+ case 0:
+ usart->char_mask = 0b11111;
+ break;
+ case 1:
+ usart->char_mask = 0b111111;
+ break;
+ case 2:
+ usart->char_mask = 0b1111111;
+ break;
+ case 3:
+ usart->char_mask = 0b11111111;
+ break;
+ case 4:
+ /* Fallthrough. */
+ case 5:
+ /* Fallthrough. */
+ case 6:
+ qemu_log_mask(
+ LOG_GUEST_ERROR,
+ "%s: Reserved character size 0x%x\n",
+ __func__,
+ mode);
+ break;
+ case 7:
+ qemu_log_mask(
+ LOG_GUEST_ERROR,
+ "%s: Nine bit character size not supported (forcing eight)\n",
+ __func__);
+ usart->char_mask = 0b11111111;
+ break;
+ default:
+ assert(0);
+ }
+}
+
+static void avr_usart_reset(DeviceState *dev)
+{
+ AVRUsartState *usart = AVR_USART(dev);
+ usart->data_valid = false;
+ usart->csra = 0b00100000;
+ usart->csrb = 0b00000000;
+ usart->csrc = 0b00000110;
+ usart->brrl = 0;
+ usart->brrh = 0;
+ update_char_mask(usart);
+ qemu_set_irq(usart->rxc_irq, 0);
+ qemu_set_irq(usart->txc_irq, 0);
+ qemu_set_irq(usart->dre_irq, 0);
+}
+
+static uint64_t avr_usart_read(void *opaque, hwaddr addr, unsigned int size)
+{
+ AVRUsartState *usart = opaque;
+ uint8_t data;
+ assert(size == 1);
+
+ if (!usart->enabled) {
+ return 0;
+ }
+
+ switch (addr) {
+ case USART_DR:
+ if (!(usart->csrb & USART_CSRB_RXEN)) {
+ /* Receiver disabled, ignore. */
+ return 0;
+ }
+ if (usart->data_valid) {
+ data = usart->data & usart->char_mask;
+ usart->data_valid = false;
+ } else {
+ data = 0;
+ }
+ usart->csra &= 0xff ^ USART_CSRA_RXC;
+ qemu_set_irq(usart->rxc_irq, 0);
+ qemu_chr_fe_accept_input(&usart->chr);
+ return data;
+ case USART_CSRA:
+ return usart->csra;
+ case USART_CSRB:
+ return usart->csrb;
+ case USART_CSRC:
+ return usart->csrc;
+ case USART_BRRL:
+ return usart->brrl;
+ case USART_BRRH:
+ return usart->brrh;
+ default:
+ qemu_log_mask(
+ LOG_GUEST_ERROR,
+ "%s: Bad offset 0x%"HWADDR_PRIx"\n",
+ __func__,
+ addr);
+ }
+ return 0;
+}
+
+static void avr_usart_write(void *opaque, hwaddr addr, uint64_t value,
+ unsigned int size)
+{
+ AVRUsartState *usart = opaque;
+ uint8_t mask;
+ uint8_t data;
+ assert((value & 0xff) == value);
+ assert(size == 1);
+
+ if (!usart->enabled) {
+ return;
+ }
+
+ switch (addr) {
+ case USART_DR:
+ if (!(usart->csrb & USART_CSRB_TXEN)) {
+ /* Transmitter disabled, ignore. */
+ return;
+ }
+ usart->csra |= USART_CSRA_TXC;
+ usart->csra |= USART_CSRA_DRE;
+ if (usart->csrb & USART_CSRB_TXCIE) {
+ qemu_set_irq(usart->txc_irq, 1);
+ usart->csra &= 0xff ^ USART_CSRA_TXC;
+ }
+ if (usart->csrb & USART_CSRB_DREIE) {
+ qemu_set_irq(usart->dre_irq, 1);
+ }
+ data = value;
+ qemu_chr_fe_write_all(&usart->chr, &data, 1);
+ break;
+ case USART_CSRA:
+ mask = 0b01000011;
+ /* Mask read-only bits. */
+ value = (value & mask) | (usart->csra & (0xff ^ mask));
+ usart->csra = value;
+ if (value & USART_CSRA_TXC) {
+ usart->csra ^= USART_CSRA_TXC;
+ qemu_set_irq(usart->txc_irq, 0);
+ }
+ if (value & USART_CSRA_MPCM) {
+ qemu_log_mask(
+ LOG_GUEST_ERROR,
+ "%s: MPCM not supported by USART\n",
+ __func__);
+ }
+ break;
+ case USART_CSRB:
+ mask = 0b11111101;
+ /* Mask read-only bits. */
+ value = (value & mask) | (usart->csrb & (0xff ^ mask));
+ usart->csrb = value;
+ if (!(value & USART_CSRB_RXEN)) {
+ /* Receiver disabled, flush input buffer. */
+ usart->data_valid = false;
+ }
+ qemu_set_irq(usart->rxc_irq,
+ ((value & USART_CSRB_RXCIE) &&
+ (usart->csra & USART_CSRA_RXC)) ? 1 : 0);
+ qemu_set_irq(usart->txc_irq,
+ ((value & USART_CSRB_TXCIE) &&
+ (usart->csra & USART_CSRA_TXC)) ? 1 : 0);
+ qemu_set_irq(usart->dre_irq,
+ ((value & USART_CSRB_DREIE) &&
+ (usart->csra & USART_CSRA_DRE)) ? 1 : 0);
+ update_char_mask(usart);
+ break;
+ case USART_CSRC:
+ usart->csrc = value;
+ if ((value & USART_CSRC_MSEL1) && (value & USART_CSRC_MSEL0)) {
+ qemu_log_mask(
+ LOG_GUEST_ERROR,
+ "%s: SPI mode not supported by USART\n",
+ __func__);
+ }
+ if ((value & USART_CSRC_MSEL1) && !(value & USART_CSRC_MSEL0)) {
+ qemu_log_mask(LOG_GUEST_ERROR, "%s: Bad USART mode\n", __func__);
+ }
+ if (!(value & USART_CSRC_PM1) && (value & USART_CSRC_PM0)) {
+ qemu_log_mask(
+ LOG_GUEST_ERROR,
+ "%s: Bad USART parity mode\n",
+ __func__);
+ }
+ update_char_mask(usart);
+ break;
+ case USART_BRRL:
+ usart->brrl = value;
+ break;
+ case USART_BRRH:
+ usart->brrh = value & 0b00001111;
+ break;
+ default:
+ qemu_log_mask(
+ LOG_GUEST_ERROR,
+ "%s: Bad offset 0x%"HWADDR_PRIx"\n",
+ __func__,
+ addr);
+ }
+}
+
+static const MemoryRegionOps avr_usart_ops = {
+ .read = avr_usart_read,
+ .write = avr_usart_write,
+ .endianness = DEVICE_NATIVE_ENDIAN,
+ .impl = {.min_access_size = 1, .max_access_size = 1}
+};
+
+static Property avr_usart_properties[] = {
+ DEFINE_PROP_CHR("chardev", AVRUsartState, chr),
+ DEFINE_PROP_END_OF_LIST(),
+};
+
+static void avr_usart_pr(void *opaque, int irq, int level)
+{
+ AVRUsartState *s = AVR_USART(opaque);
+
+ s->enabled = !level;
+
+ if (!s->enabled) {
+ avr_usart_reset(DEVICE(s));
+ }
+}
+
+static void avr_usart_init(Object *obj)
+{
+ AVRUsartState *s = AVR_USART(obj);
+ sysbus_init_irq(SYS_BUS_DEVICE(obj), &s->rxc_irq);
+ sysbus_init_irq(SYS_BUS_DEVICE(obj), &s->dre_irq);
+ sysbus_init_irq(SYS_BUS_DEVICE(obj), &s->txc_irq);
+ memory_region_init_io(&s->mmio, obj, &avr_usart_ops, s, TYPE_AVR_USART, 7);
+ sysbus_init_mmio(SYS_BUS_DEVICE(obj), &s->mmio);
+ qdev_init_gpio_in(DEVICE(s), avr_usart_pr, 1);
+ s->enabled = true;
+}
+
+static void avr_usart_realize(DeviceState *dev, Error **errp)
+{
+ AVRUsartState *s = AVR_USART(dev);
+ qemu_chr_fe_set_handlers(&s->chr, avr_usart_can_receive,
+ avr_usart_receive, NULL, NULL,
+ s, NULL, true);
+ avr_usart_reset(dev);
+}
+
+static void avr_usart_class_init(ObjectClass *klass, void *data)
+{
+ DeviceClass *dc = DEVICE_CLASS(klass);
+
+ dc->reset = avr_usart_reset;
+ device_class_set_props(dc, avr_usart_properties);
+ dc->realize = avr_usart_realize;
+}
+
+static const TypeInfo avr_usart_info = {
+ .name = TYPE_AVR_USART,
+ .parent = TYPE_SYS_BUS_DEVICE,
+ .instance_size = sizeof(AVRUsartState),
+ .instance_init = avr_usart_init,
+ .class_init = avr_usart_class_init,
+};
+
+static void avr_usart_register_types(void)
+{
+ type_register_static(&avr_usart_info);
+}
+
+type_init(avr_usart_register_types)
diff --git a/include/hw/char/avr_usart.h b/include/hw/char/avr_usart.h
new file mode 100644
index 0000000000..5739aaf26f
--- /dev/null
+++ b/include/hw/char/avr_usart.h
@@ -0,0 +1,93 @@
+/*
+ * AVR USART
+ *
+ * Copyright (c) 2018 University of Kent
+ * Author: Sarah Harris
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, see
+ * <http://www.gnu.org/licenses/lgpl-2.1.html>
+ */
+
+#ifndef HW_CHAR_AVR_USART_H
+#define HW_CHAR_AVR_USART_H
+
+#include "hw/sysbus.h"
+#include "chardev/char-fe.h"
+#include "hw/hw.h"
+
+/* Offsets of registers. */
+#define USART_DR 0x06
+#define USART_CSRA 0x00
+#define USART_CSRB 0x01
+#define USART_CSRC 0x02
+#define USART_BRRH 0x05
+#define USART_BRRL 0x04
+
+/* Relevant bits in regiters. */
+#define USART_CSRA_RXC (1 << 7)
+#define USART_CSRA_TXC (1 << 6)
+#define USART_CSRA_DRE (1 << 5)
+#define USART_CSRA_MPCM (1 << 0)
+
+#define USART_CSRB_RXCIE (1 << 7)
+#define USART_CSRB_TXCIE (1 << 6)
+#define USART_CSRB_DREIE (1 << 5)
+#define USART_CSRB_RXEN (1 << 4)
+#define USART_CSRB_TXEN (1 << 3)
+#define USART_CSRB_CSZ2 (1 << 2)
+#define USART_CSRB_RXB8 (1 << 1)
+#define USART_CSRB_TXB8 (1 << 0)
+
+#define USART_CSRC_MSEL1 (1 << 7)
+#define USART_CSRC_MSEL0 (1 << 6)
+#define USART_CSRC_PM1 (1 << 5)
+#define USART_CSRC_PM0 (1 << 4)
+#define USART_CSRC_CSZ1 (1 << 2)
+#define USART_CSRC_CSZ0 (1 << 1)
+
+#define TYPE_AVR_USART "avr-usart"
+#define AVR_USART(obj) \
+ OBJECT_CHECK(AVRUsartState, (obj), TYPE_AVR_USART)
+
+typedef struct {
+ /* <private> */
+ SysBusDevice parent_obj;
+
+ /* <public> */
+ MemoryRegion mmio;
+
+ CharBackend chr;
+
+ bool enabled;
+
+ uint8_t data;
+ bool data_valid;
+ uint8_t char_mask;
+ /* Control and Status Registers */
+ uint8_t csra;
+ uint8_t csrb;
+ uint8_t csrc;
+ /* Baud Rate Registers (low/high byte) */
+ uint8_t brrh;
+ uint8_t brrl;
+
+ /* Receive Complete */
+ qemu_irq rxc_irq;
+ /* Transmit Complete */
+ qemu_irq txc_irq;
+ /* Data Register Empty */
+ qemu_irq dre_irq;
+} AVRUsartState;
+
+#endif /* HW_CHAR_AVR_USART_H */
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