--- /dev/null
+/*
+ * nRF51 SoC UART emulation
+ *
+ * See nRF51 Series Reference Manual, "29 Universal Asynchronous
+ * Receiver/Transmitter" for hardware specifications:
+ * http://infocenter.nordicsemi.com/pdf/nRF51_RM_v3.0.pdf
+ *
+ * Copyright (c) 2018 Julia Suvorova <jusual@mail.ru>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 or
+ * (at your option) any later version.
+ */
+
+#include "qemu/osdep.h"
+#include "qemu/log.h"
+#include "hw/char/nrf51_uart.h"
+#include "trace.h"
+
+static void nrf51_uart_update_irq(NRF51UARTState *s)
+{
+ bool irq = false;
+
+ irq |= (s->reg[R_UART_RXDRDY] &&
+ (s->reg[R_UART_INTEN] & R_UART_INTEN_RXDRDY_MASK));
+ irq |= (s->reg[R_UART_TXDRDY] &&
+ (s->reg[R_UART_INTEN] & R_UART_INTEN_TXDRDY_MASK));
+ irq |= (s->reg[R_UART_ERROR] &&
+ (s->reg[R_UART_INTEN] & R_UART_INTEN_ERROR_MASK));
+ irq |= (s->reg[R_UART_RXTO] &&
+ (s->reg[R_UART_INTEN] & R_UART_INTEN_RXTO_MASK));
+
+ qemu_set_irq(s->irq, irq);
+}
+
+static uint64_t uart_read(void *opaque, hwaddr addr, unsigned int size)
+{
+ NRF51UARTState *s = NRF51_UART(opaque);
+ uint64_t r;
+
+ if (!s->enabled) {
+ return 0;
+ }
+
+ switch (addr) {
+ case A_UART_RXD:
+ r = s->rx_fifo[s->rx_fifo_pos];
+ if (s->rx_started && s->rx_fifo_len) {
+ s->rx_fifo_pos = (s->rx_fifo_pos + 1) % UART_FIFO_LENGTH;
+ s->rx_fifo_len--;
+ if (s->rx_fifo_len) {
+ s->reg[R_UART_RXDRDY] = 1;
+ nrf51_uart_update_irq(s);
+ }
+ qemu_chr_fe_accept_input(&s->chr);
+ }
+ break;
+ case A_UART_INTENSET:
+ case A_UART_INTENCLR:
+ case A_UART_INTEN:
+ r = s->reg[R_UART_INTEN];
+ break;
+ default:
+ r = s->reg[addr / 4];
+ break;
+ }
+
+ trace_nrf51_uart_read(addr, r, size);
+
+ return r;
+}
+
+static gboolean uart_transmit(GIOChannel *chan, GIOCondition cond, void *opaque)
+{
+ NRF51UARTState *s = NRF51_UART(opaque);
+ int r;
+ uint8_t c = s->reg[R_UART_TXD];
+
+ s->watch_tag = 0;
+
+ r = qemu_chr_fe_write(&s->chr, &c, 1);
+ if (r <= 0) {
+ s->watch_tag = qemu_chr_fe_add_watch(&s->chr, G_IO_OUT | G_IO_HUP,
+ uart_transmit, s);
+ if (!s->watch_tag) {
+ /* The hardware has no transmit error reporting,
+ * so silently drop the byte
+ */
+ goto buffer_drained;
+ }
+ return FALSE;
+ }
+
+buffer_drained:
+ s->reg[R_UART_TXDRDY] = 1;
+ s->pending_tx_byte = false;
+ return FALSE;
+}
+
+static void uart_cancel_transmit(NRF51UARTState *s)
+{
+ if (s->watch_tag) {
+ g_source_remove(s->watch_tag);
+ s->watch_tag = 0;
+ }
+}
+
+static void uart_write(void *opaque, hwaddr addr,
+ uint64_t value, unsigned int size)
+{
+ NRF51UARTState *s = NRF51_UART(opaque);
+
+ trace_nrf51_uart_write(addr, value, size);
+
+ if (!s->enabled && (addr != A_UART_ENABLE)) {
+ return;
+ }
+
+ switch (addr) {
+ case A_UART_TXD:
+ if (!s->pending_tx_byte && s->tx_started) {
+ s->reg[R_UART_TXD] = value;
+ s->pending_tx_byte = true;
+ uart_transmit(NULL, G_IO_OUT, s);
+ }
+ break;
+ case A_UART_INTEN:
+ s->reg[R_UART_INTEN] = value;
+ break;
+ case A_UART_INTENSET:
+ s->reg[R_UART_INTEN] |= value;
+ break;
+ case A_UART_INTENCLR:
+ s->reg[R_UART_INTEN] &= ~value;
+ break;
+ case A_UART_TXDRDY ... A_UART_RXTO:
+ s->reg[addr / 4] = value;
+ break;
+ case A_UART_ERRORSRC:
+ s->reg[addr / 4] &= ~value;
+ break;
+ case A_UART_RXD:
+ break;
+ case A_UART_RXDRDY:
+ if (value == 0) {
+ s->reg[R_UART_RXDRDY] = 0;
+ }
+ break;
+ case A_UART_STARTTX:
+ if (value == 1) {
+ s->tx_started = true;
+ }
+ break;
+ case A_UART_STARTRX:
+ if (value == 1) {
+ s->rx_started = true;
+ }
+ break;
+ case A_UART_ENABLE:
+ if (value) {
+ if (value == 4) {
+ s->enabled = true;
+ }
+ break;
+ }
+ s->enabled = false;
+ value = 1;
+ /* fall through */
+ case A_UART_SUSPEND:
+ case A_UART_STOPTX:
+ if (value == 1) {
+ s->tx_started = false;
+ }
+ /* fall through */
+ case A_UART_STOPRX:
+ if (addr != A_UART_STOPTX && value == 1) {
+ s->rx_started = false;
+ s->reg[R_UART_RXTO] = 1;
+ }
+ break;
+ default:
+ s->reg[addr / 4] = value;
+ break;
+ }
+ nrf51_uart_update_irq(s);
+}
+
+static const MemoryRegionOps uart_ops = {
+ .read = uart_read,
+ .write = uart_write,
+ .endianness = DEVICE_LITTLE_ENDIAN,
+};
+
+static void nrf51_uart_reset(DeviceState *dev)
+{
+ NRF51UARTState *s = NRF51_UART(dev);
+
+ s->pending_tx_byte = 0;
+
+ uart_cancel_transmit(s);
+
+ memset(s->reg, 0, sizeof(s->reg));
+
+ s->reg[R_UART_PSELRTS] = 0xFFFFFFFF;
+ s->reg[R_UART_PSELTXD] = 0xFFFFFFFF;
+ s->reg[R_UART_PSELCTS] = 0xFFFFFFFF;
+ s->reg[R_UART_PSELRXD] = 0xFFFFFFFF;
+ s->reg[R_UART_BAUDRATE] = 0x4000000;
+
+ s->rx_fifo_len = 0;
+ s->rx_fifo_pos = 0;
+ s->rx_started = false;
+ s->tx_started = false;
+ s->enabled = false;
+}
+
+static void uart_receive(void *opaque, const uint8_t *buf, int size)
+{
+
+ NRF51UARTState *s = NRF51_UART(opaque);
+ int i;
+
+ if (size == 0 || s->rx_fifo_len >= UART_FIFO_LENGTH) {
+ return;
+ }
+
+ for (i = 0; i < size; i++) {
+ uint32_t pos = (s->rx_fifo_pos + s->rx_fifo_len) % UART_FIFO_LENGTH;
+ s->rx_fifo[pos] = buf[i];
+ s->rx_fifo_len++;
+ }
+
+ s->reg[R_UART_RXDRDY] = 1;
+ nrf51_uart_update_irq(s);
+}
+
+static int uart_can_receive(void *opaque)
+{
+ NRF51UARTState *s = NRF51_UART(opaque);
+
+ return s->rx_started ? (UART_FIFO_LENGTH - s->rx_fifo_len) : 0;
+}
+
+static void uart_event(void *opaque, int event)
+{
+ NRF51UARTState *s = NRF51_UART(opaque);
+
+ if (event == CHR_EVENT_BREAK) {
+ s->reg[R_UART_ERRORSRC] |= 3;
+ s->reg[R_UART_ERROR] = 1;
+ nrf51_uart_update_irq(s);
+ }
+}
+
+static void nrf51_uart_realize(DeviceState *dev, Error **errp)
+{
+ NRF51UARTState *s = NRF51_UART(dev);
+
+ qemu_chr_fe_set_handlers(&s->chr, uart_can_receive, uart_receive,
+ uart_event, NULL, s, NULL, true);
+}
+
+static void nrf51_uart_init(Object *obj)
+{
+ NRF51UARTState *s = NRF51_UART(obj);
+ SysBusDevice *sbd = SYS_BUS_DEVICE(obj);
+
+ memory_region_init_io(&s->iomem, obj, &uart_ops, s,
+ "nrf51_soc.uart", UART_SIZE);
+ sysbus_init_mmio(sbd, &s->iomem);
+ sysbus_init_irq(sbd, &s->irq);
+}
+
+static int nrf51_uart_post_load(void *opaque, int version_id)
+{
+ NRF51UARTState *s = NRF51_UART(opaque);
+
+ if (s->pending_tx_byte) {
+ s->watch_tag = qemu_chr_fe_add_watch(&s->chr, G_IO_OUT | G_IO_HUP,
+ uart_transmit, s);
+ }
+
+ return 0;
+}
+
+static const VMStateDescription nrf51_uart_vmstate = {
+ .name = "nrf51_soc.uart",
+ .post_load = nrf51_uart_post_load,
+ .fields = (VMStateField[]) {
+ VMSTATE_UINT32_ARRAY(reg, NRF51UARTState, 0x56C),
+ VMSTATE_UINT8_ARRAY(rx_fifo, NRF51UARTState, UART_FIFO_LENGTH),
+ VMSTATE_UINT32(rx_fifo_pos, NRF51UARTState),
+ VMSTATE_UINT32(rx_fifo_len, NRF51UARTState),
+ VMSTATE_BOOL(rx_started, NRF51UARTState),
+ VMSTATE_BOOL(tx_started, NRF51UARTState),
+ VMSTATE_BOOL(pending_tx_byte, NRF51UARTState),
+ VMSTATE_BOOL(enabled, NRF51UARTState),
+ VMSTATE_END_OF_LIST()
+ }
+};
+
+static Property nrf51_uart_properties[] = {
+ DEFINE_PROP_CHR("chardev", NRF51UARTState, chr),
+ DEFINE_PROP_END_OF_LIST(),
+};
+
+static void nrf51_uart_class_init(ObjectClass *klass, void *data)
+{
+ DeviceClass *dc = DEVICE_CLASS(klass);
+
+ dc->reset = nrf51_uart_reset;
+ dc->realize = nrf51_uart_realize;
+ dc->props = nrf51_uart_properties;
+ dc->vmsd = &nrf51_uart_vmstate;
+}
+
+static const TypeInfo nrf51_uart_info = {
+ .name = TYPE_NRF51_UART,
+ .parent = TYPE_SYS_BUS_DEVICE,
+ .instance_size = sizeof(NRF51UARTState),
+ .instance_init = nrf51_uart_init,
+ .class_init = nrf51_uart_class_init
+};
+
+static void nrf51_uart_register_types(void)
+{
+ type_register_static(&nrf51_uart_info);
+}
+
+type_init(nrf51_uart_register_types)
--- /dev/null
+/*
+ * nRF51 SoC UART emulation
+ *
+ * Copyright (c) 2018 Julia Suvorova <jusual@mail.ru>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 or
+ * (at your option) any later version.
+ */
+
+#ifndef NRF51_UART_H
+#define NRF51_UART_H
+
+#include "hw/sysbus.h"
+#include "chardev/char-fe.h"
+#include "hw/registerfields.h"
+
+#define UART_FIFO_LENGTH 6
+#define UART_BASE 0x40002000
+#define UART_SIZE 0x1000
+
+#define TYPE_NRF51_UART "nrf51_soc.uart"
+#define NRF51_UART(obj) OBJECT_CHECK(NRF51UARTState, (obj), TYPE_NRF51_UART)
+
+REG32(UART_STARTRX, 0x000)
+REG32(UART_STOPRX, 0x004)
+REG32(UART_STARTTX, 0x008)
+REG32(UART_STOPTX, 0x00C)
+REG32(UART_SUSPEND, 0x01C)
+
+REG32(UART_CTS, 0x100)
+REG32(UART_NCTS, 0x104)
+REG32(UART_RXDRDY, 0x108)
+REG32(UART_TXDRDY, 0x11C)
+REG32(UART_ERROR, 0x124)
+REG32(UART_RXTO, 0x144)
+
+REG32(UART_INTEN, 0x300)
+ FIELD(UART_INTEN, CTS, 0, 1)
+ FIELD(UART_INTEN, NCTS, 1, 1)
+ FIELD(UART_INTEN, RXDRDY, 2, 1)
+ FIELD(UART_INTEN, TXDRDY, 7, 1)
+ FIELD(UART_INTEN, ERROR, 9, 1)
+ FIELD(UART_INTEN, RXTO, 17, 1)
+REG32(UART_INTENSET, 0x304)
+REG32(UART_INTENCLR, 0x308)
+REG32(UART_ERRORSRC, 0x480)
+REG32(UART_ENABLE, 0x500)
+REG32(UART_PSELRTS, 0x508)
+REG32(UART_PSELTXD, 0x50C)
+REG32(UART_PSELCTS, 0x510)
+REG32(UART_PSELRXD, 0x514)
+REG32(UART_RXD, 0x518)
+REG32(UART_TXD, 0x51C)
+REG32(UART_BAUDRATE, 0x524)
+REG32(UART_CONFIG, 0x56C)
+
+typedef struct NRF51UARTState {
+ SysBusDevice parent_obj;
+
+ MemoryRegion iomem;
+ CharBackend chr;
+ qemu_irq irq;
+ guint watch_tag;
+
+ uint8_t rx_fifo[UART_FIFO_LENGTH];
+ unsigned int rx_fifo_pos;
+ unsigned int rx_fifo_len;
+
+ uint32_t reg[0x56C];
+
+ bool rx_started;
+ bool tx_started;
+ bool pending_tx_byte;
+ bool enabled;
+} NRF51UARTState;
+
+#endif