Merge remote-tracking branch 'remotes/alistair/tags/pull-riscv-to-apply-20200619-3' into staging

This is a range of patches for RISC-V.

Some key points are:
 - Generalise the CPU init functions
 - Support the SiFive revB machine
 - Improvements to the Hypervisor implementation and error checking
 - Connect some OpenTitan devices
 - Changes to the sifive_u machine to support U-boot

v2:
 - Fix missing realise assert

# gpg: Signature made Fri 19 Jun 2020 17:34:34 BST
# gpg:                using RSA key F6C4AC46D4934868D3B8CE8F21E10D29DF977054
# gpg: Good signature from "Alistair Francis <alistair@alistair23.me>" [full]
# Primary key fingerprint: F6C4 AC46 D493 4868 D3B8  CE8F 21E1 0D29 DF97 7054

* remotes/alistair/tags/pull-riscv-to-apply-20200619-3: (32 commits)
  hw/riscv: sifive_u: Add a dummy DDR memory controller device
  hw/riscv: sifive_u: Sort the SoC memmap table entries
  hw/riscv: sifive_u: Support different boot source per MSEL pin state
  hw/riscv: sifive: Change SiFive E/U CPU reset vector to 0x1004
  target/riscv: Rename IBEX CPU init routine
  hw/riscv: sifive_u: Add a new property msel for MSEL pin state
  hw/riscv: sifive_u: Rename serial property get/set functions to a generic name
  hw/riscv: sifive_u: Add reset functionality
  hw/riscv: sifive_gpio: Do not blindly trigger output IRQs
  hw/riscv: sifive_u: Hook a GPIO controller
  hw/riscv: sifive_gpio: Add a new 'ngpio' property
  hw/riscv: sifive_gpio: Clean up the codes
  hw/riscv: sifive_u: Generate device tree node for OTP
  hw/riscv: sifive_u: Simplify the GEM IRQ connect code a little bit
  hw/riscv: opentitan: Remove the riscv_ prefix of the machine* and soc* functions
  hw/riscv: sifive_e: Remove the riscv_ prefix of the machine* and soc* functions
  target/riscv: Use a smaller guess size for no-MMU PMP
  riscv/opentitan: Connect the UART device
  riscv/opentitan: Connect the PLIC device
  hw/intc: Initial commit of lowRISC Ibex PLIC
  ...

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

9 files changed, 1010 insertions, 82 deletions

diff --git a/hw/char/Makefile.objs b/hw/char/Makefile.objs
index 9e9a6c1..633996b 100644
--- a/hw/char/Makefile.objs
+++ b/hw/char/Makefile.objs
@@ -12,6 +12,7 @@ common-obj-$(CONFIG_VIRTIO_SERIAL) += virtio-console.o
 common-obj-$(CONFIG_XILINX) += xilinx_uartlite.o
 common-obj-$(CONFIG_XEN) += xen_console.o
 common-obj-$(CONFIG_CADENCE) += cadence_uart.o
+common-obj-$(CONFIG_IBEX) += ibex_uart.o
 
 common-obj-$(CONFIG_EXYNOS4) += exynos4210_uart.o
 common-obj-$(CONFIG_COLDFIRE) += mcf_uart.o
diff --git a/hw/char/ibex_uart.c b/hw/char/ibex_uart.c
new file mode 100644
index 0000000..3e0dd99
--- /dev/null
+++ b/hw/char/ibex_uart.c
@@ -0,0 +1,492 @@
+/*
+ * QEMU lowRISC Ibex UART device
+ *
+ * Copyright (c) 2020 Western Digital
+ *
+ * For details check the documentation here:
+ *    https://docs.opentitan.org/hw/ip/uart/doc/
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include "qemu/osdep.h"
+#include "hw/char/ibex_uart.h"
+#include "hw/irq.h"
+#include "hw/qdev-properties.h"
+#include "migration/vmstate.h"
+#include "qemu/log.h"
+#include "qemu/module.h"
+
+static void ibex_uart_update_irqs(IbexUartState *s)
+{
+    if (s->uart_intr_state & s->uart_intr_enable & INTR_STATE_TX_WATERMARK) {
+        qemu_set_irq(s->tx_watermark, 1);
+    } else {
+        qemu_set_irq(s->tx_watermark, 0);
+    }
+
+    if (s->uart_intr_state & s->uart_intr_enable & INTR_STATE_RX_WATERMARK) {
+        qemu_set_irq(s->rx_watermark, 1);
+    } else {
+        qemu_set_irq(s->rx_watermark, 0);
+    }
+
+    if (s->uart_intr_state & s->uart_intr_enable & INTR_STATE_TX_EMPTY) {
+        qemu_set_irq(s->tx_empty, 1);
+    } else {
+        qemu_set_irq(s->tx_empty, 0);
+    }
+
+    if (s->uart_intr_state & s->uart_intr_enable & INTR_STATE_RX_OVERFLOW) {
+        qemu_set_irq(s->rx_overflow, 1);
+    } else {
+        qemu_set_irq(s->rx_overflow, 0);
+    }
+}
+
+static int ibex_uart_can_receive(void *opaque)
+{
+    IbexUartState *s = opaque;
+
+    if (s->uart_ctrl & UART_CTRL_RX_ENABLE) {
+        return 1;
+    }
+
+    return 0;
+}
+
+static void ibex_uart_receive(void *opaque, const uint8_t *buf, int size)
+{
+    IbexUartState *s = opaque;
+    uint8_t rx_fifo_level = (s->uart_fifo_ctrl & FIFO_CTRL_RXILVL)
+                            >> FIFO_CTRL_RXILVL_SHIFT;
+
+    s->uart_rdata = *buf;
+
+    s->uart_status &= ~UART_STATUS_RXIDLE;
+    s->uart_status &= ~UART_STATUS_RXEMPTY;
+
+    if (size > rx_fifo_level) {
+        s->uart_intr_state |= INTR_STATE_RX_WATERMARK;
+    }
+
+    ibex_uart_update_irqs(s);
+}
+
+static gboolean ibex_uart_xmit(GIOChannel *chan, GIOCondition cond,
+                               void *opaque)
+{
+    IbexUartState *s = opaque;
+    uint8_t tx_fifo_level = (s->uart_fifo_ctrl & FIFO_CTRL_TXILVL)
+                            >> FIFO_CTRL_TXILVL_SHIFT;
+    int ret;
+
+    /* instant drain the fifo when there's no back-end */
+    if (!qemu_chr_fe_backend_connected(&s->chr)) {
+        s->tx_level = 0;
+        return FALSE;
+    }
+
+    if (!s->tx_level) {
+        s->uart_status &= ~UART_STATUS_TXFULL;
+        s->uart_status |= UART_STATUS_TXEMPTY;
+        s->uart_intr_state |= INTR_STATE_TX_EMPTY;
+        s->uart_intr_state &= ~INTR_STATE_TX_WATERMARK;
+        ibex_uart_update_irqs(s);
+        return FALSE;
+    }
+
+    ret = qemu_chr_fe_write(&s->chr, s->tx_fifo, s->tx_level);
+
+    if (ret >= 0) {
+        s->tx_level -= ret;
+        memmove(s->tx_fifo, s->tx_fifo + ret, s->tx_level);
+    }
+
+    if (s->tx_level) {
+        guint r = qemu_chr_fe_add_watch(&s->chr, G_IO_OUT | G_IO_HUP,
+                                        ibex_uart_xmit, s);
+        if (!r) {
+            s->tx_level = 0;
+            return FALSE;
+        }
+    }
+
+    /* Clear the TX Full bit */
+    if (s->tx_level != IBEX_UART_TX_FIFO_SIZE) {
+        s->uart_status &= ~UART_STATUS_TXFULL;
+    }
+
+    /* Disable the TX_WATERMARK IRQ */
+    if (s->tx_level < tx_fifo_level) {
+        s->uart_intr_state &= ~INTR_STATE_TX_WATERMARK;
+    }
+
+    /* Set TX empty */
+    if (s->tx_level == 0) {
+        s->uart_status |= UART_STATUS_TXEMPTY;
+        s->uart_intr_state |= INTR_STATE_TX_EMPTY;
+    }
+
+    ibex_uart_update_irqs(s);
+    return FALSE;
+}
+
+static void uart_write_tx_fifo(IbexUartState *s, const uint8_t *buf,
+                               int size)
+{
+    uint64_t current_time = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
+    uint8_t tx_fifo_level = (s->uart_fifo_ctrl & FIFO_CTRL_TXILVL)
+                            >> FIFO_CTRL_TXILVL_SHIFT;
+
+    if (size > IBEX_UART_TX_FIFO_SIZE - s->tx_level) {
+        size = IBEX_UART_TX_FIFO_SIZE - s->tx_level;
+        qemu_log_mask(LOG_GUEST_ERROR, "ibex_uart: TX FIFO overflow");
+    }
+
+    memcpy(s->tx_fifo + s->tx_level, buf, size);
+    s->tx_level += size;
+
+    if (s->tx_level > 0) {
+        s->uart_status &= ~UART_STATUS_TXEMPTY;
+    }
+
+    if (s->tx_level >= tx_fifo_level) {
+        s->uart_intr_state |= INTR_STATE_TX_WATERMARK;
+        ibex_uart_update_irqs(s);
+    }
+
+    if (s->tx_level == IBEX_UART_TX_FIFO_SIZE) {
+        s->uart_status |= UART_STATUS_TXFULL;
+    }
+
+    timer_mod(s->fifo_trigger_handle, current_time +
+              (s->char_tx_time * 4));
+}
+
+static void ibex_uart_reset(DeviceState *dev)
+{
+    IbexUartState *s = IBEX_UART(dev);
+
+    s->uart_intr_state = 0x00000000;
+    s->uart_intr_state = 0x00000000;
+    s->uart_intr_enable = 0x00000000;
+    s->uart_ctrl = 0x00000000;
+    s->uart_status = 0x0000003c;
+    s->uart_rdata = 0x00000000;
+    s->uart_fifo_ctrl = 0x00000000;
+    s->uart_fifo_status = 0x00000000;
+    s->uart_ovrd = 0x00000000;
+    s->uart_val = 0x00000000;
+    s->uart_timeout_ctrl = 0x00000000;
+
+    s->tx_level = 0;
+
+    s->char_tx_time = (NANOSECONDS_PER_SECOND / 230400) * 10;
+
+    ibex_uart_update_irqs(s);
+}
+
+static uint64_t ibex_uart_read(void *opaque, hwaddr addr,
+                                       unsigned int size)
+{
+    IbexUartState *s = opaque;
+    uint64_t retvalue = 0;
+
+    switch (addr) {
+    case IBEX_UART_INTR_STATE:
+        retvalue = s->uart_intr_state;
+        break;
+    case IBEX_UART_INTR_ENABLE:
+        retvalue = s->uart_intr_enable;
+        break;
+    case IBEX_UART_INTR_TEST:
+        qemu_log_mask(LOG_GUEST_ERROR,
+                      "%s: wdata is write only\n", __func__);
+        break;
+
+    case IBEX_UART_CTRL:
+        retvalue = s->uart_ctrl;
+        break;
+    case IBEX_UART_STATUS:
+        retvalue = s->uart_status;
+        break;
+
+    case IBEX_UART_RDATA:
+        retvalue = s->uart_rdata;
+        if (s->uart_ctrl & UART_CTRL_RX_ENABLE) {
+            qemu_chr_fe_accept_input(&s->chr);
+
+            s->uart_status |= UART_STATUS_RXIDLE;
+            s->uart_status |= UART_STATUS_RXEMPTY;
+        }
+        break;
+    case IBEX_UART_WDATA:
+        qemu_log_mask(LOG_GUEST_ERROR,
+                      "%s: wdata is write only\n", __func__);
+        break;
+
+    case IBEX_UART_FIFO_CTRL:
+        retvalue = s->uart_fifo_ctrl;
+        break;
+    case IBEX_UART_FIFO_STATUS:
+        retvalue = s->uart_fifo_status;
+
+        retvalue |= s->tx_level & 0x1F;
+
+        qemu_log_mask(LOG_UNIMP,
+                      "%s: RX fifos are not supported\n", __func__);
+        break;
+
+    case IBEX_UART_OVRD:
+        retvalue = s->uart_ovrd;
+        qemu_log_mask(LOG_UNIMP,
+                      "%s: ovrd is not supported\n", __func__);
+        break;
+    case IBEX_UART_VAL:
+        retvalue = s->uart_val;
+        qemu_log_mask(LOG_UNIMP,
+                      "%s: val is not supported\n", __func__);
+        break;
+    case IBEX_UART_TIMEOUT_CTRL:
+        retvalue = s->uart_timeout_ctrl;
+        qemu_log_mask(LOG_UNIMP,
+                      "%s: timeout_ctrl is not supported\n", __func__);
+        break;
+    default:
+        qemu_log_mask(LOG_GUEST_ERROR,
+                      "%s: Bad offset 0x%"HWADDR_PRIx"\n", __func__, addr);
+        return 0;
+    }
+
+    return retvalue;
+}
+
+static void ibex_uart_write(void *opaque, hwaddr addr,
+                                  uint64_t val64, unsigned int size)
+{
+    IbexUartState *s = opaque;
+    uint32_t value = val64;
+
+    switch (addr) {
+    case IBEX_UART_INTR_STATE:
+        /* Write 1 clear */
+        s->uart_intr_state &= ~value;
+        ibex_uart_update_irqs(s);
+        break;
+    case IBEX_UART_INTR_ENABLE:
+        s->uart_intr_enable = value;
+        ibex_uart_update_irqs(s);
+        break;
+    case IBEX_UART_INTR_TEST:
+        s->uart_intr_state |= value;
+        ibex_uart_update_irqs(s);
+        break;
+
+    case IBEX_UART_CTRL:
+        s->uart_ctrl = value;
+
+        if (value & UART_CTRL_NF) {
+            qemu_log_mask(LOG_UNIMP,
+                          "%s: UART_CTRL_NF is not supported\n", __func__);
+        }
+        if (value & UART_CTRL_SLPBK) {
+            qemu_log_mask(LOG_UNIMP,
+                          "%s: UART_CTRL_SLPBK is not supported\n", __func__);
+        }
+        if (value & UART_CTRL_LLPBK) {
+            qemu_log_mask(LOG_UNIMP,
+                          "%s: UART_CTRL_LLPBK is not supported\n", __func__);
+        }
+        if (value & UART_CTRL_PARITY_EN) {
+            qemu_log_mask(LOG_UNIMP,
+                          "%s: UART_CTRL_PARITY_EN is not supported\n",
+                          __func__);
+        }
+        if (value & UART_CTRL_PARITY_ODD) {
+            qemu_log_mask(LOG_UNIMP,
+                          "%s: UART_CTRL_PARITY_ODD is not supported\n",
+                          __func__);
+        }
+        if (value & UART_CTRL_RXBLVL) {
+            qemu_log_mask(LOG_UNIMP,
+                          "%s: UART_CTRL_RXBLVL is not supported\n", __func__);
+        }
+        if (value & UART_CTRL_NCO) {
+            uint64_t baud = ((value & UART_CTRL_NCO) >> 16);
+            baud *= 1000;
+            baud /= 2 ^ 20;
+
+            s->char_tx_time = (NANOSECONDS_PER_SECOND / baud) * 10;
+        }
+        break;
+    case IBEX_UART_STATUS:
+        qemu_log_mask(LOG_GUEST_ERROR,
+                      "%s: status is read only\n", __func__);
+        break;
+
+    case IBEX_UART_RDATA:
+        qemu_log_mask(LOG_GUEST_ERROR,
+                      "%s: rdata is read only\n", __func__);
+        break;
+    case IBEX_UART_WDATA:
+        uart_write_tx_fifo(s, (uint8_t *) &value, 1);
+        break;
+
+    case IBEX_UART_FIFO_CTRL:
+        s->uart_fifo_ctrl = value;
+
+        if (value & FIFO_CTRL_RXRST) {
+            qemu_log_mask(LOG_UNIMP,
+                          "%s: RX fifos are not supported\n", __func__);
+        }
+        if (value & FIFO_CTRL_TXRST) {
+            s->tx_level = 0;
+        }
+        break;
+    case IBEX_UART_FIFO_STATUS:
+        qemu_log_mask(LOG_GUEST_ERROR,
+                      "%s: fifo_status is read only\n", __func__);
+        break;
+
+    case IBEX_UART_OVRD:
+        s->uart_ovrd = value;
+        qemu_log_mask(LOG_UNIMP,
+                      "%s: ovrd is not supported\n", __func__);
+        break;
+    case IBEX_UART_VAL:
+        qemu_log_mask(LOG_GUEST_ERROR,
+                      "%s: val is read only\n", __func__);
+        break;
+    case IBEX_UART_TIMEOUT_CTRL:
+        s->uart_timeout_ctrl = value;
+        qemu_log_mask(LOG_UNIMP,
+                      "%s: timeout_ctrl is not supported\n", __func__);
+        break;
+    default:
+        qemu_log_mask(LOG_GUEST_ERROR,
+                      "%s: Bad offset 0x%"HWADDR_PRIx"\n", __func__, addr);
+    }
+}
+
+static void fifo_trigger_update(void *opaque)
+{
+    IbexUartState *s = opaque;
+
+    if (s->uart_ctrl & UART_CTRL_TX_ENABLE) {
+        ibex_uart_xmit(NULL, G_IO_OUT, s);
+    }
+}
+
+static const MemoryRegionOps ibex_uart_ops = {
+    .read = ibex_uart_read,
+    .write = ibex_uart_write,
+    .endianness = DEVICE_NATIVE_ENDIAN,
+    .impl.min_access_size = 4,
+    .impl.max_access_size = 4,
+};
+
+static int ibex_uart_post_load(void *opaque, int version_id)
+{
+    IbexUartState *s = opaque;
+
+    ibex_uart_update_irqs(s);
+    return 0;
+}
+
+static const VMStateDescription vmstate_ibex_uart = {
+    .name = TYPE_IBEX_UART,
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .post_load = ibex_uart_post_load,
+    .fields = (VMStateField[]) {
+        VMSTATE_UINT8_ARRAY(tx_fifo, IbexUartState,
+                            IBEX_UART_TX_FIFO_SIZE),
+        VMSTATE_UINT32(tx_level, IbexUartState),
+        VMSTATE_UINT64(char_tx_time, IbexUartState),
+        VMSTATE_TIMER_PTR(fifo_trigger_handle, IbexUartState),
+        VMSTATE_UINT32(uart_intr_state, IbexUartState),
+        VMSTATE_UINT32(uart_intr_enable, IbexUartState),
+        VMSTATE_UINT32(uart_ctrl, IbexUartState),
+        VMSTATE_UINT32(uart_status, IbexUartState),
+        VMSTATE_UINT32(uart_rdata, IbexUartState),
+        VMSTATE_UINT32(uart_fifo_ctrl, IbexUartState),
+        VMSTATE_UINT32(uart_fifo_status, IbexUartState),
+        VMSTATE_UINT32(uart_ovrd, IbexUartState),
+        VMSTATE_UINT32(uart_val, IbexUartState),
+        VMSTATE_UINT32(uart_timeout_ctrl, IbexUartState),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
+static Property ibex_uart_properties[] = {
+    DEFINE_PROP_CHR("chardev", IbexUartState, chr),
+    DEFINE_PROP_END_OF_LIST(),
+};
+
+static void ibex_uart_init(Object *obj)
+{
+    IbexUartState *s = IBEX_UART(obj);
+
+    sysbus_init_irq(SYS_BUS_DEVICE(obj), &s->tx_watermark);
+    sysbus_init_irq(SYS_BUS_DEVICE(obj), &s->rx_watermark);
+    sysbus_init_irq(SYS_BUS_DEVICE(obj), &s->tx_empty);
+    sysbus_init_irq(SYS_BUS_DEVICE(obj), &s->rx_overflow);
+
+    memory_region_init_io(&s->mmio, obj, &ibex_uart_ops, s,
+                          TYPE_IBEX_UART, 0x400);
+    sysbus_init_mmio(SYS_BUS_DEVICE(obj), &s->mmio);
+}
+
+static void ibex_uart_realize(DeviceState *dev, Error **errp)
+{
+    IbexUartState *s = IBEX_UART(dev);
+
+    s->fifo_trigger_handle = timer_new_ns(QEMU_CLOCK_VIRTUAL,
+                                          fifo_trigger_update, s);
+
+    qemu_chr_fe_set_handlers(&s->chr, ibex_uart_can_receive,
+                             ibex_uart_receive, NULL, NULL,
+                             s, NULL, true);
+}
+
+static void ibex_uart_class_init(ObjectClass *klass, void *data)
+{
+    DeviceClass *dc = DEVICE_CLASS(klass);
+
+    dc->reset = ibex_uart_reset;
+    dc->realize = ibex_uart_realize;
+    dc->vmsd = &vmstate_ibex_uart;
+    device_class_set_props(dc, ibex_uart_properties);
+}
+
+static const TypeInfo ibex_uart_info = {
+    .name          = TYPE_IBEX_UART,
+    .parent        = TYPE_SYS_BUS_DEVICE,
+    .instance_size = sizeof(IbexUartState),
+    .instance_init = ibex_uart_init,
+    .class_init    = ibex_uart_class_init,
+};
+
+static void ibex_uart_register_types(void)
+{
+    type_register_static(&ibex_uart_info);
+}
+
+type_init(ibex_uart_register_types)
diff --git a/hw/intc/Makefile.objs b/hw/intc/Makefile.objs
index f726d87..a61e672 100644
--- a/hw/intc/Makefile.objs
+++ b/hw/intc/Makefile.objs
@@ -49,3 +49,4 @@ obj-$(CONFIG_ARM_GIC) += arm_gicv3_cpuif.o
 obj-$(CONFIG_MIPS_CPS) += mips_gic.o
 obj-$(CONFIG_NIOS2) += nios2_iic.o
 obj-$(CONFIG_OMPIC) += ompic.o
+obj-$(CONFIG_IBEX) += ibex_plic.o
diff --git a/hw/intc/ibex_plic.c b/hw/intc/ibex_plic.c
new file mode 100644
index 0000000..4107951
--- /dev/null
+++ b/hw/intc/ibex_plic.c
@@ -0,0 +1,261 @@
+/*
+ * QEMU RISC-V lowRISC Ibex PLIC
+ *
+ * Copyright (c) 2020 Western Digital
+ *
+ * Documentation avaliable: https://docs.opentitan.org/hw/ip/rv_plic/doc/
+ *
+ * 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 "qemu/log.h"
+#include "hw/qdev-properties.h"
+#include "hw/core/cpu.h"
+#include "hw/boards.h"
+#include "hw/pci/msi.h"
+#include "target/riscv/cpu_bits.h"
+#include "target/riscv/cpu.h"
+#include "hw/intc/ibex_plic.h"
+
+static bool addr_between(uint32_t addr, uint32_t base, uint32_t num)
+{
+    uint32_t end = base + (num * 0x04);
+
+    if (addr >= base && addr < end) {
+        return true;
+    }
+
+    return false;
+}
+
+static void ibex_plic_irqs_set_pending(IbexPlicState *s, int irq, bool level)
+{
+    int pending_num = irq / 32;
+
+    s->pending[pending_num] |= level << (irq % 32);
+}
+
+static bool ibex_plic_irqs_pending(IbexPlicState *s, uint32_t context)
+{
+    int i;
+
+    for (i = 0; i < s->pending_num; i++) {
+        uint32_t irq_num = ctz64(s->pending[i]) + (i * 32);
+
+        if (!(s->pending[i] & s->enable[i])) {
+            /* No pending and enabled IRQ */
+            continue;
+        }
+
+        if (s->priority[irq_num] > s->threshold) {
+            if (!s->claim) {
+                s->claim = irq_num;
+            }
+            return true;
+        }
+    }
+
+    return false;
+}
+
+static void ibex_plic_update(IbexPlicState *s)
+{
+    CPUState *cpu;
+    int level, i;
+
+    for (i = 0; i < s->num_cpus; i++) {
+        cpu = qemu_get_cpu(i);
+
+        if (!cpu) {
+            continue;
+        }
+
+        level = ibex_plic_irqs_pending(s, 0);
+
+        riscv_cpu_update_mip(RISCV_CPU(cpu), MIP_MEIP, BOOL_TO_MASK(level));
+    }
+}
+
+static void ibex_plic_reset(DeviceState *dev)
+{
+    IbexPlicState *s = IBEX_PLIC(dev);
+
+    s->threshold = 0x00000000;
+    s->claim = 0x00000000;
+}
+
+static uint64_t ibex_plic_read(void *opaque, hwaddr addr,
+                               unsigned int size)
+{
+    IbexPlicState *s = opaque;
+    int offset;
+    uint32_t ret = 0;
+
+    if (addr_between(addr, s->pending_base, s->pending_num)) {
+        offset = (addr - s->pending_base) / 4;
+        ret = s->pending[offset];
+    } else if (addr_between(addr, s->source_base, s->source_num)) {
+        qemu_log_mask(LOG_UNIMP,
+                      "%s: Interrupt source mode not supported\n", __func__);
+    } else if (addr_between(addr, s->priority_base, s->priority_num)) {
+        offset = (addr - s->priority_base) / 4;
+        ret = s->priority[offset];
+    } else if (addr_between(addr, s->enable_base, s->enable_num)) {
+        offset = (addr - s->enable_base) / 4;
+        ret = s->enable[offset];
+    } else if (addr_between(addr, s->threshold_base, 1)) {
+        ret = s->threshold;
+    } else if (addr_between(addr, s->claim_base, 1)) {
+        int pending_num = s->claim / 32;
+        s->pending[pending_num] &= ~(1 << (s->claim % 32));
+
+        ret = s->claim;
+    }
+
+    return ret;
+}
+
+static void ibex_plic_write(void *opaque, hwaddr addr,
+                            uint64_t value, unsigned int size)
+{
+    IbexPlicState *s = opaque;
+
+    if (addr_between(addr, s->pending_base, s->pending_num)) {
+        qemu_log_mask(LOG_GUEST_ERROR,
+                      "%s: Pending registers are read only\n", __func__);
+    } else if (addr_between(addr, s->source_base, s->source_num)) {
+        qemu_log_mask(LOG_UNIMP,
+                      "%s: Interrupt source mode not supported\n", __func__);
+    } else if (addr_between(addr, s->priority_base, s->priority_num)) {
+        uint32_t irq = ((addr - s->priority_base) >> 2) + 1;
+        s->priority[irq] = value & 7;
+    } else if (addr_between(addr, s->enable_base, s->enable_num)) {
+        uint32_t enable_reg = (addr - s->enable_base) / 4;
+
+        s->enable[enable_reg] = value;
+    } else if (addr_between(addr, s->threshold_base, 1)) {
+        s->threshold = value & 3;
+    } else if (addr_between(addr, s->claim_base, 1)) {
+        if (s->claim == value) {
+            /* Interrupt was completed */
+            s->claim = 0;
+        }
+    }
+
+    ibex_plic_update(s);
+}
+
+static const MemoryRegionOps ibex_plic_ops = {
+    .read = ibex_plic_read,
+    .write = ibex_plic_write,
+    .endianness = DEVICE_NATIVE_ENDIAN,
+    .valid = {
+        .min_access_size = 4,
+        .max_access_size = 4
+    }
+};
+
+static void ibex_plic_irq_request(void *opaque, int irq, int level)
+{
+    IbexPlicState *s = opaque;
+
+    ibex_plic_irqs_set_pending(s, irq, level > 0);
+    ibex_plic_update(s);
+}
+
+static Property ibex_plic_properties[] = {
+    DEFINE_PROP_UINT32("num-cpus", IbexPlicState, num_cpus, 1),
+    DEFINE_PROP_UINT32("num-sources", IbexPlicState, num_sources, 80),
+
+    DEFINE_PROP_UINT32("pending-base", IbexPlicState, pending_base, 0),
+    DEFINE_PROP_UINT32("pending-num", IbexPlicState, pending_num, 3),
+
+    DEFINE_PROP_UINT32("source-base", IbexPlicState, source_base, 0x0c),
+    DEFINE_PROP_UINT32("source-num", IbexPlicState, source_num, 3),
+
+    DEFINE_PROP_UINT32("priority-base", IbexPlicState, priority_base, 0x18),
+    DEFINE_PROP_UINT32("priority-num", IbexPlicState, priority_num, 80),
+
+    DEFINE_PROP_UINT32("enable-base", IbexPlicState, enable_base, 0x200),
+    DEFINE_PROP_UINT32("enable-num", IbexPlicState, enable_num, 3),
+
+    DEFINE_PROP_UINT32("threshold-base", IbexPlicState, threshold_base, 0x20c),
+
+    DEFINE_PROP_UINT32("claim-base", IbexPlicState, claim_base, 0x210),
+    DEFINE_PROP_END_OF_LIST(),
+};
+
+static void ibex_plic_init(Object *obj)
+{
+    IbexPlicState *s = IBEX_PLIC(obj);
+
+    memory_region_init_io(&s->mmio, obj, &ibex_plic_ops, s,
+                          TYPE_IBEX_PLIC, 0x400);
+    sysbus_init_mmio(SYS_BUS_DEVICE(obj), &s->mmio);
+}
+
+static void ibex_plic_realize(DeviceState *dev, Error **errp)
+{
+    IbexPlicState *s = IBEX_PLIC(dev);
+    int i;
+
+    s->pending = g_new0(uint32_t, s->pending_num);
+    s->source = g_new0(uint32_t, s->source_num);
+    s->priority = g_new0(uint32_t, s->priority_num);
+    s->enable = g_new0(uint32_t, s->enable_num);
+
+    qdev_init_gpio_in(dev, ibex_plic_irq_request, s->num_sources);
+
+    /*
+     * We can't allow the supervisor to control SEIP as this would allow the
+     * supervisor to clear a pending external interrupt which will result in
+     * a lost interrupt in the case a PLIC is attached. The SEIP bit must be
+     * hardware controlled when a PLIC is attached.
+     */
+    MachineState *ms = MACHINE(qdev_get_machine());
+    unsigned int smp_cpus = ms->smp.cpus;
+    for (i = 0; i < smp_cpus; i++) {
+        RISCVCPU *cpu = RISCV_CPU(qemu_get_cpu(i));
+        if (riscv_cpu_claim_interrupts(cpu, MIP_SEIP) < 0) {
+            error_report("SEIP already claimed");
+            exit(1);
+        }
+    }
+
+    msi_nonbroken = true;
+}
+
+static void ibex_plic_class_init(ObjectClass *klass, void *data)
+{
+    DeviceClass *dc = DEVICE_CLASS(klass);
+
+    dc->reset = ibex_plic_reset;
+    device_class_set_props(dc, ibex_plic_properties);
+    dc->realize = ibex_plic_realize;
+}
+
+static const TypeInfo ibex_plic_info = {
+    .name          = TYPE_IBEX_PLIC,
+    .parent        = TYPE_SYS_BUS_DEVICE,
+    .instance_size = sizeof(IbexPlicState),
+    .instance_init = ibex_plic_init,
+    .class_init    = ibex_plic_class_init,
+};
+
+static void ibex_plic_register_types(void)
+{
+    type_register_static(&ibex_plic_info);
+}
+
+type_init(ibex_plic_register_types)
diff --git a/hw/riscv/Kconfig b/hw/riscv/Kconfig
index 94d1957..28947ef 100644
--- a/hw/riscv/Kconfig
+++ b/hw/riscv/Kconfig
@@ -4,6 +4,9 @@ config HTIF
 config HART
     bool
 
+config IBEX
+    bool
+
 config SIFIVE
     bool
     select MSI_NONBROKEN
@@ -29,6 +32,7 @@ config SPIKE
 
 config OPENTITAN
     bool
+    select IBEX
     select HART
     select UNIMP
 
diff --git a/hw/riscv/opentitan.c b/hw/riscv/opentitan.c
index f6776da..19223e4 100644
--- a/hw/riscv/opentitan.c
+++ b/hw/riscv/opentitan.c
@@ -25,12 +25,14 @@
 #include "hw/misc/unimp.h"
 #include "hw/riscv/boot.h"
 #include "exec/address-spaces.h"
+#include "qemu/units.h"
+#include "sysemu/sysemu.h"
 
 static const struct MemmapEntry {
     hwaddr base;
     hwaddr size;
 } ibex_memmap[] = {
-    [IBEX_ROM] =            {  0x00008000,   0xc000 },
+    [IBEX_ROM] =            {  0x00008000, 16 * KiB },
     [IBEX_RAM] =            {  0x10000000,  0x10000 },
     [IBEX_FLASH] =          {  0x20000000,  0x80000 },
     [IBEX_UART] =           {  0x40000000,  0x10000 },
@@ -51,7 +53,7 @@ static const struct MemmapEntry {
     [IBEX_PADCTRL] =        {  0x40160000,  0x10000 }
 };
 
-static void riscv_opentitan_init(MachineState *machine)
+static void opentitan_board_init(MachineState *machine)
 {
     const struct MemmapEntry *memmap = ibex_memmap;
     OpenTitanState *s = g_new0(OpenTitanState, 1);
@@ -68,7 +70,6 @@ static void riscv_opentitan_init(MachineState *machine)
     memory_region_add_subregion(sys_mem,
         memmap[IBEX_RAM].base, main_mem);
 
-
     if (machine->firmware) {
         riscv_load_firmware(machine->firmware, memmap[IBEX_RAM].base, NULL);
     }
@@ -78,29 +79,34 @@ static void riscv_opentitan_init(MachineState *machine)
     }
 }
 
-static void riscv_opentitan_machine_init(MachineClass *mc)
+static void opentitan_machine_init(MachineClass *mc)
 {
     mc->desc = "RISC-V Board compatible with OpenTitan";
-    mc->init = riscv_opentitan_init;
+    mc->init = opentitan_board_init;
     mc->max_cpus = 1;
     mc->default_cpu_type = TYPE_RISCV_CPU_IBEX;
 }
 
-DEFINE_MACHINE("opentitan", riscv_opentitan_machine_init)
+DEFINE_MACHINE("opentitan", opentitan_machine_init)
 
-static void riscv_lowrisc_ibex_soc_init(Object *obj)
+static void lowrisc_ibex_soc_init(Object *obj)
 {
     LowRISCIbexSoCState *s = RISCV_IBEX_SOC(obj);
 
     object_initialize_child(obj, "cpus", &s->cpus, TYPE_RISCV_HART_ARRAY);
+
+    object_initialize_child(obj, "plic", &s->plic, TYPE_IBEX_PLIC);
+
+    object_initialize_child(obj, "uart", &s->uart, TYPE_IBEX_UART);
 }
 
-static void riscv_lowrisc_ibex_soc_realize(DeviceState *dev_soc, Error **errp)
+static void lowrisc_ibex_soc_realize(DeviceState *dev_soc, Error **errp)
 {
     const struct MemmapEntry *memmap = ibex_memmap;
     MachineState *ms = MACHINE(qdev_get_machine());
     LowRISCIbexSoCState *s = RISCV_IBEX_SOC(dev_soc);
     MemoryRegion *sys_mem = get_system_memory();
+    Error *err = NULL;
 
     object_property_set_str(OBJECT(&s->cpus), ms->cpu_type, "cpu-type",
                             &error_abort);
@@ -120,8 +126,35 @@ static void riscv_lowrisc_ibex_soc_realize(DeviceState *dev_soc, Error **errp)
     memory_region_add_subregion(sys_mem, memmap[IBEX_FLASH].base,
                                 &s->flash_mem);
 
-    create_unimplemented_device("riscv.lowrisc.ibex.uart",
-        memmap[IBEX_UART].base, memmap[IBEX_UART].size);
+    /* PLIC */
+    sysbus_realize(SYS_BUS_DEVICE(&s->plic), &err);
+    if (err != NULL) {
+        error_propagate(errp, err);
+        return;
+    }
+    sysbus_mmio_map(SYS_BUS_DEVICE(&s->plic), 0, memmap[IBEX_PLIC].base);
+
+    /* UART */
+    qdev_prop_set_chr(DEVICE(&(s->uart)), "chardev", serial_hd(0));
+    sysbus_realize(SYS_BUS_DEVICE(&s->uart), &err);
+    if (err != NULL) {
+        error_propagate(errp, err);
+        return;
+    }
+    sysbus_mmio_map(SYS_BUS_DEVICE(&s->uart), 0, memmap[IBEX_UART].base);
+    sysbus_connect_irq(SYS_BUS_DEVICE(&s->uart),
+                       0, qdev_get_gpio_in(DEVICE(&s->plic),
+                       IBEX_UART_TX_WATERMARK_IRQ));
+    sysbus_connect_irq(SYS_BUS_DEVICE(&s->uart),
+                       1, qdev_get_gpio_in(DEVICE(&s->plic),
+                       IBEX_UART_RX_WATERMARK_IRQ));
+    sysbus_connect_irq(SYS_BUS_DEVICE(&s->uart),
+                       2, qdev_get_gpio_in(DEVICE(&s->plic),
+                       IBEX_UART_TX_EMPTY_IRQ));
+    sysbus_connect_irq(SYS_BUS_DEVICE(&s->uart),
+                       3, qdev_get_gpio_in(DEVICE(&s->plic),
+                       IBEX_UART_RX_OVERFLOW_IRQ));
+
     create_unimplemented_device("riscv.lowrisc.ibex.gpio",
         memmap[IBEX_GPIO].base, memmap[IBEX_GPIO].size);
     create_unimplemented_device("riscv.lowrisc.ibex.spi",
@@ -140,8 +173,6 @@ static void riscv_lowrisc_ibex_soc_realize(DeviceState *dev_soc, Error **errp)
         memmap[IBEX_AES].base, memmap[IBEX_AES].size);
     create_unimplemented_device("riscv.lowrisc.ibex.hmac",
         memmap[IBEX_HMAC].base, memmap[IBEX_HMAC].size);
-    create_unimplemented_device("riscv.lowrisc.ibex.plic",
-        memmap[IBEX_PLIC].base, memmap[IBEX_PLIC].size);
     create_unimplemented_device("riscv.lowrisc.ibex.pinmux",
         memmap[IBEX_PINMUX].base, memmap[IBEX_PINMUX].size);
     create_unimplemented_device("riscv.lowrisc.ibex.alert_handler",
@@ -154,26 +185,26 @@ static void riscv_lowrisc_ibex_soc_realize(DeviceState *dev_soc, Error **errp)
         memmap[IBEX_PADCTRL].base, memmap[IBEX_PADCTRL].size);
 }
 
-static void riscv_lowrisc_ibex_soc_class_init(ObjectClass *oc, void *data)
+static void lowrisc_ibex_soc_class_init(ObjectClass *oc, void *data)
 {
     DeviceClass *dc = DEVICE_CLASS(oc);
 
-    dc->realize = riscv_lowrisc_ibex_soc_realize;
+    dc->realize = lowrisc_ibex_soc_realize;
     /* Reason: Uses serial_hds in realize function, thus can't be used twice */
     dc->user_creatable = false;
 }
 
-static const TypeInfo riscv_lowrisc_ibex_soc_type_info = {
+static const TypeInfo lowrisc_ibex_soc_type_info = {
     .name = TYPE_RISCV_IBEX_SOC,
     .parent = TYPE_DEVICE,
     .instance_size = sizeof(LowRISCIbexSoCState),
-    .instance_init = riscv_lowrisc_ibex_soc_init,
-    .class_init = riscv_lowrisc_ibex_soc_class_init,
+    .instance_init = lowrisc_ibex_soc_init,
+    .class_init = lowrisc_ibex_soc_class_init,
 };
 
-static void riscv_lowrisc_ibex_soc_register_types(void)
+static void lowrisc_ibex_soc_register_types(void)
 {
-    type_register_static(&riscv_lowrisc_ibex_soc_type_info);
+    type_register_static(&lowrisc_ibex_soc_type_info);
 }
 
-type_init(riscv_lowrisc_ibex_soc_register_types)
+type_init(lowrisc_ibex_soc_register_types)
diff --git a/hw/riscv/sifive_e.c b/hw/riscv/sifive_e.c
index 1c17d02..0cb66ac 100644
--- a/hw/riscv/sifive_e.c
+++ b/hw/riscv/sifive_e.c
@@ -75,7 +75,7 @@ static const struct MemmapEntry {
     [SIFIVE_E_DTIM] =     { 0x80000000,     0x4000 }
 };
 
-static void riscv_sifive_e_init(MachineState *machine)
+static void sifive_e_machine_init(MachineState *machine)
 {
     const struct MemmapEntry *memmap = sifive_e_memmap;
 
@@ -95,10 +95,16 @@ static void riscv_sifive_e_init(MachineState *machine)
         memmap[SIFIVE_E_DTIM].base, main_mem);
 
     /* Mask ROM reset vector */
-    uint32_t reset_vec[2] = {
-        0x204002b7,        /* 0x1000: lui     t0,0x20400 */
-        0x00028067,        /* 0x1004: jr      t0 */
-    };
+    uint32_t reset_vec[4];
+
+    if (s->revb) {
+        reset_vec[1] = 0x200102b7;  /* 0x1004: lui     t0,0x20010 */
+    } else {
+        reset_vec[1] = 0x204002b7;  /* 0x1004: lui     t0,0x20400 */
+    }
+    reset_vec[2] = 0x00028067;      /* 0x1008: jr      t0 */
+
+    reset_vec[0] = reset_vec[3] = 0;
 
     /* copy in the reset vector in little_endian byte order */
     for (i = 0; i < sizeof(reset_vec) >> 2; i++) {
@@ -112,8 +118,30 @@ static void riscv_sifive_e_init(MachineState *machine)
     }
 }
 
+static bool sifive_e_machine_get_revb(Object *obj, Error **errp)
+{
+    SiFiveEState *s = RISCV_E_MACHINE(obj);
+
+    return s->revb;
+}
+
+static void sifive_e_machine_set_revb(Object *obj, bool value, Error **errp)
+{
+    SiFiveEState *s = RISCV_E_MACHINE(obj);
+
+    s->revb = value;
+}
+
 static void sifive_e_machine_instance_init(Object *obj)
 {
+    SiFiveEState *s = RISCV_E_MACHINE(obj);
+
+    s->revb = false;
+    object_property_add_bool(obj, "revb", sifive_e_machine_get_revb,
+                             sifive_e_machine_set_revb);
+    object_property_set_description(obj, "revb",
+                                    "Set on to tell QEMU that it should model "
+                                    "the revB HiFive1 board");
 }
 
 static void sifive_e_machine_class_init(ObjectClass *oc, void *data)
@@ -121,7 +149,7 @@ static void sifive_e_machine_class_init(ObjectClass *oc, void *data)
     MachineClass *mc = MACHINE_CLASS(oc);
 
     mc->desc = "RISC-V Board compatible with SiFive E SDK";
-    mc->init = riscv_sifive_e_init;
+    mc->init = sifive_e_machine_init;
     mc->max_cpus = 1;
     mc->default_cpu_type = SIFIVE_E_CPU;
 }
@@ -141,7 +169,7 @@ static void sifive_e_machine_init_register_types(void)
 
 type_init(sifive_e_machine_init_register_types)
 
-static void riscv_sifive_e_soc_init(Object *obj)
+static void sifive_e_soc_init(Object *obj)
 {
     MachineState *ms = MACHINE(qdev_get_machine());
     SiFiveESoCState *s = RISCV_E_SOC(obj);
@@ -153,7 +181,7 @@ static void riscv_sifive_e_soc_init(Object *obj)
                             TYPE_SIFIVE_GPIO);
 }
 
-static void riscv_sifive_e_soc_realize(DeviceState *dev, Error **errp)
+static void sifive_e_soc_realize(DeviceState *dev, Error **errp)
 {
     MachineState *ms = MACHINE(qdev_get_machine());
     const struct MemmapEntry *memmap = sifive_e_memmap;
@@ -236,26 +264,26 @@ static void riscv_sifive_e_soc_realize(DeviceState *dev, Error **errp)
         &s->xip_mem);
 }
 
-static void riscv_sifive_e_soc_class_init(ObjectClass *oc, void *data)
+static void sifive_e_soc_class_init(ObjectClass *oc, void *data)
 {
     DeviceClass *dc = DEVICE_CLASS(oc);
 
-    dc->realize = riscv_sifive_e_soc_realize;
+    dc->realize = sifive_e_soc_realize;
     /* Reason: Uses serial_hds in realize function, thus can't be used twice */
     dc->user_creatable = false;
 }
 
-static const TypeInfo riscv_sifive_e_soc_type_info = {
+static const TypeInfo sifive_e_soc_type_info = {
     .name = TYPE_RISCV_E_SOC,
     .parent = TYPE_DEVICE,
     .instance_size = sizeof(SiFiveESoCState),
-    .instance_init = riscv_sifive_e_soc_init,
-    .class_init = riscv_sifive_e_soc_class_init,
+    .instance_init = sifive_e_soc_init,
+    .class_init = sifive_e_soc_class_init,
 };
 
-static void riscv_sifive_e_soc_register_types(void)
+static void sifive_e_soc_register_types(void)
 {
-    type_register_static(&riscv_sifive_e_soc_type_info);
+    type_register_static(&sifive_e_soc_type_info);
 }
 
-type_init(riscv_sifive_e_soc_register_types)
+type_init(sifive_e_soc_register_types)
diff --git a/hw/riscv/sifive_gpio.c b/hw/riscv/sifive_gpio.c
index 5c7c596..aac6b44 100644
--- a/hw/riscv/sifive_gpio.c
+++ b/hw/riscv/sifive_gpio.c
@@ -1,5 +1,5 @@
 /*
- * sifive System-on-Chip general purpose input/output register definition
+ * SiFive System-on-Chip general purpose input/output register definition
  *
  * Copyright 2019 AdaCore
  *
@@ -14,13 +14,13 @@
 #include "qemu/osdep.h"
 #include "qemu/log.h"
 #include "hw/irq.h"
+#include "hw/qdev-properties.h"
 #include "hw/riscv/sifive_gpio.h"
 #include "migration/vmstate.h"
 #include "trace.h"
 
 static void update_output_irq(SIFIVEGPIOState *s)
 {
-
     uint32_t pending;
     uint32_t pin;
 
@@ -29,7 +29,7 @@ static void update_output_irq(SIFIVEGPIOState *s)
     pending |= s->rise_ip & s->rise_ie;
     pending |= s->fall_ip & s->fall_ie;
 
-    for (int i = 0; i < SIFIVE_GPIO_PINS; i++) {
+    for (int i = 0; i < s->ngpio; i++) {
         pin = 1 << i;
         qemu_set_irq(s->irq[i], (pending & pin) != 0);
         trace_sifive_gpio_update_output_irq(i, (pending & pin) != 0);
@@ -42,7 +42,7 @@ static void update_state(SIFIVEGPIOState *s)
     bool prev_ival, in, in_mask, port, out_xor, pull, output_en, input_en,
         rise_ip, fall_ip, low_ip, high_ip, oval, actual_value, ival;
 
-    for (i = 0; i < SIFIVE_GPIO_PINS; i++) {
+    for (i = 0; i < s->ngpio; i++) {
 
         prev_ival = extract32(s->value, i, 1);
         in        = extract32(s->in, i, 1);
@@ -76,7 +76,9 @@ static void update_state(SIFIVEGPIOState *s)
             actual_value = pull;
         }
 
-        qemu_set_irq(s->output[i], actual_value);
+        if (output_en) {
+            qemu_set_irq(s->output[i], actual_value);
+        }
 
         /* Input value */
         ival = input_en && actual_value;
@@ -186,7 +188,7 @@ static uint64_t sifive_gpio_read(void *opaque, hwaddr offset, unsigned int size)
 }
 
 static void sifive_gpio_write(void *opaque, hwaddr offset,
-                       uint64_t value, unsigned int size)
+                              uint64_t value, unsigned int size)
 {
     SIFIVEGPIOState *s = SIFIVE_GPIO(opaque);
 
@@ -318,7 +320,6 @@ static void sifive_gpio_reset(DeviceState *dev)
     s->out_xor = 0;
     s->in = 0;
     s->in_mask = 0;
-
 }
 
 static const VMStateDescription vmstate_sifive_gpio = {
@@ -342,43 +343,49 @@ static const VMStateDescription vmstate_sifive_gpio = {
         VMSTATE_UINT32(iof_en,    SIFIVEGPIOState),
         VMSTATE_UINT32(iof_sel,   SIFIVEGPIOState),
         VMSTATE_UINT32(out_xor,   SIFIVEGPIOState),
-        VMSTATE_UINT32(in, SIFIVEGPIOState),
-        VMSTATE_UINT32(in_mask, SIFIVEGPIOState),
+        VMSTATE_UINT32(in,        SIFIVEGPIOState),
+        VMSTATE_UINT32(in_mask,   SIFIVEGPIOState),
         VMSTATE_END_OF_LIST()
     }
 };
 
-static void sifive_gpio_init(Object *obj)
+static Property sifive_gpio_properties[] = {
+    DEFINE_PROP_UINT32("ngpio", SIFIVEGPIOState, ngpio, SIFIVE_GPIO_PINS),
+    DEFINE_PROP_END_OF_LIST(),
+};
+
+static void sifive_gpio_realize(DeviceState *dev, Error **errp)
 {
-    SIFIVEGPIOState *s = SIFIVE_GPIO(obj);
+    SIFIVEGPIOState *s = SIFIVE_GPIO(dev);
 
-    memory_region_init_io(&s->mmio, obj, &gpio_ops, s,
+    memory_region_init_io(&s->mmio, OBJECT(dev), &gpio_ops, s,
             TYPE_SIFIVE_GPIO, SIFIVE_GPIO_SIZE);
-    sysbus_init_mmio(SYS_BUS_DEVICE(obj), &s->mmio);
 
+    sysbus_init_mmio(SYS_BUS_DEVICE(dev), &s->mmio);
 
-    for (int i = 0; i < SIFIVE_GPIO_PINS; i++) {
-        sysbus_init_irq(SYS_BUS_DEVICE(obj), &s->irq[i]);
+    for (int i = 0; i < s->ngpio; i++) {
+        sysbus_init_irq(SYS_BUS_DEVICE(dev), &s->irq[i]);
     }
 
-    qdev_init_gpio_in(DEVICE(s), sifive_gpio_set, SIFIVE_GPIO_PINS);
-    qdev_init_gpio_out(DEVICE(s), s->output, SIFIVE_GPIO_PINS);
+    qdev_init_gpio_in(DEVICE(s), sifive_gpio_set, s->ngpio);
+    qdev_init_gpio_out(DEVICE(s), s->output, s->ngpio);
 }
 
 static void sifive_gpio_class_init(ObjectClass *klass, void *data)
 {
     DeviceClass *dc = DEVICE_CLASS(klass);
 
+    device_class_set_props(dc, sifive_gpio_properties);
     dc->vmsd = &vmstate_sifive_gpio;
+    dc->realize = sifive_gpio_realize;
     dc->reset = sifive_gpio_reset;
-    dc->desc = "sifive GPIO";
+    dc->desc = "SiFive GPIO";
 }
 
 static const TypeInfo sifive_gpio_info = {
     .name = TYPE_SIFIVE_GPIO,
     .parent = TYPE_SYS_BUS_DEVICE,
     .instance_size = sizeof(SIFIVEGPIOState),
-    .instance_init = sifive_gpio_init,
     .class_init = sifive_gpio_class_init
 };
 
diff --git a/hw/riscv/sifive_u.c b/hw/riscv/sifive_u.c
index ea197ab..7d051e7 100644
--- a/hw/riscv/sifive_u.c
+++ b/hw/riscv/sifive_u.c
@@ -11,8 +11,9 @@
  * 1) CLINT (Core Level Interruptor)
  * 2) PLIC (Platform Level Interrupt Controller)
  * 3) PRCI (Power, Reset, Clock, Interrupt)
- * 4) OTP (One-Time Programmable) memory with stored serial number
- * 5) GEM (Gigabit Ethernet Controller) and management block
+ * 4) GPIO (General Purpose Input/Output Controller)
+ * 5) OTP (One-Time Programmable) memory with stored serial number
+ * 6) GEM (Gigabit Ethernet Controller) and management block
  *
  * This board currently generates devicetree dynamically that indicates at least
  * two harts and up to five harts.
@@ -36,6 +37,7 @@
 #include "qapi/error.h"
 #include "qapi/visitor.h"
 #include "hw/boards.h"
+#include "hw/irq.h"
 #include "hw/loader.h"
 #include "hw/sysbus.h"
 #include "hw/char/serial.h"
@@ -52,6 +54,7 @@
 #include "net/eth.h"
 #include "sysemu/arch_init.h"
 #include "sysemu/device_tree.h"
+#include "sysemu/runstate.h"
 #include "sysemu/sysemu.h"
 #include "exec/address-spaces.h"
 
@@ -75,11 +78,13 @@ static const struct MemmapEntry {
     [SIFIVE_U_PRCI] =     { 0x10000000,     0x1000 },
     [SIFIVE_U_UART0] =    { 0x10010000,     0x1000 },
     [SIFIVE_U_UART1] =    { 0x10011000,     0x1000 },
+    [SIFIVE_U_GPIO] =     { 0x10060000,     0x1000 },
     [SIFIVE_U_OTP] =      { 0x10070000,     0x1000 },
-    [SIFIVE_U_FLASH0] =   { 0x20000000, 0x10000000 },
-    [SIFIVE_U_DRAM] =     { 0x80000000,        0x0 },
     [SIFIVE_U_GEM] =      { 0x10090000,     0x2000 },
     [SIFIVE_U_GEM_MGMT] = { 0x100a0000,     0x1000 },
+    [SIFIVE_U_DMC] =      { 0x100b0000,    0x10000 },
+    [SIFIVE_U_FLASH0] =   { 0x20000000, 0x10000000 },
+    [SIFIVE_U_DRAM] =     { 0x80000000,        0x0 },
 };
 
 #define OTP_SERIAL          1
@@ -94,7 +99,7 @@ static void create_fdt(SiFiveUState *s, const struct MemmapEntry *memmap,
     uint32_t *cells;
     char *nodename;
     char ethclk_names[] = "pclk\0hclk";
-    uint32_t plic_phandle, prci_phandle, phandle = 1;
+    uint32_t plic_phandle, prci_phandle, gpio_phandle, phandle = 1;
     uint32_t hfclk_phandle, rtcclk_phandle, phy_phandle;
 
     fdt = s->fdt = create_device_tree(&s->fdt_size);
@@ -207,6 +212,17 @@ static void create_fdt(SiFiveUState *s, const struct MemmapEntry *memmap,
     g_free(cells);
     g_free(nodename);
 
+    nodename = g_strdup_printf("/soc/otp@%lx",
+        (long)memmap[SIFIVE_U_OTP].base);
+    qemu_fdt_add_subnode(fdt, nodename);
+    qemu_fdt_setprop_cell(fdt, nodename, "fuse-count", SIFIVE_U_OTP_REG_SIZE);
+    qemu_fdt_setprop_cells(fdt, nodename, "reg",
+        0x0, memmap[SIFIVE_U_OTP].base,
+        0x0, memmap[SIFIVE_U_OTP].size);
+    qemu_fdt_setprop_string(fdt, nodename, "compatible",
+        "sifive,fu540-c000-otp");
+    g_free(nodename);
+
     prci_phandle = phandle++;
     nodename = g_strdup_printf("/soc/clock-controller@%lx",
         (long)memmap[SIFIVE_U_PRCI].base);
@@ -257,6 +273,36 @@ static void create_fdt(SiFiveUState *s, const struct MemmapEntry *memmap,
     g_free(cells);
     g_free(nodename);
 
+    gpio_phandle = phandle++;
+    nodename = g_strdup_printf("/soc/gpio@%lx",
+        (long)memmap[SIFIVE_U_GPIO].base);
+    qemu_fdt_add_subnode(fdt, nodename);
+    qemu_fdt_setprop_cell(fdt, nodename, "phandle", gpio_phandle);
+    qemu_fdt_setprop_cells(fdt, nodename, "clocks",
+        prci_phandle, PRCI_CLK_TLCLK);
+    qemu_fdt_setprop_cell(fdt, nodename, "#interrupt-cells", 2);
+    qemu_fdt_setprop(fdt, nodename, "interrupt-controller", NULL, 0);
+    qemu_fdt_setprop_cell(fdt, nodename, "#gpio-cells", 2);
+    qemu_fdt_setprop(fdt, nodename, "gpio-controller", NULL, 0);
+    qemu_fdt_setprop_cells(fdt, nodename, "reg",
+        0x0, memmap[SIFIVE_U_GPIO].base,
+        0x0, memmap[SIFIVE_U_GPIO].size);
+    qemu_fdt_setprop_cells(fdt, nodename, "interrupts", SIFIVE_U_GPIO_IRQ0,
+        SIFIVE_U_GPIO_IRQ1, SIFIVE_U_GPIO_IRQ2, SIFIVE_U_GPIO_IRQ3,
+        SIFIVE_U_GPIO_IRQ4, SIFIVE_U_GPIO_IRQ5, SIFIVE_U_GPIO_IRQ6,
+        SIFIVE_U_GPIO_IRQ7, SIFIVE_U_GPIO_IRQ8, SIFIVE_U_GPIO_IRQ9,
+        SIFIVE_U_GPIO_IRQ10, SIFIVE_U_GPIO_IRQ11, SIFIVE_U_GPIO_IRQ12,
+        SIFIVE_U_GPIO_IRQ13, SIFIVE_U_GPIO_IRQ14, SIFIVE_U_GPIO_IRQ15);
+    qemu_fdt_setprop_cell(fdt, nodename, "interrupt-parent", plic_phandle);
+    qemu_fdt_setprop_string(fdt, nodename, "compatible", "sifive,gpio0");
+    g_free(nodename);
+
+    nodename = g_strdup_printf("/gpio-restart");
+    qemu_fdt_add_subnode(fdt, nodename);
+    qemu_fdt_setprop_cells(fdt, nodename, "gpios", gpio_phandle, 10, 1);
+    qemu_fdt_setprop_string(fdt, nodename, "compatible", "gpio-restart");
+    g_free(nodename);
+
     phy_phandle = phandle++;
     nodename = g_strdup_printf("/soc/ethernet@%lx",
         (long)memmap[SIFIVE_U_GEM].base);
@@ -317,6 +363,14 @@ static void create_fdt(SiFiveUState *s, const struct MemmapEntry *memmap,
     g_free(nodename);
 }
 
+static void sifive_u_machine_reset(void *opaque, int n, int level)
+{
+    /* gpio pin active low triggers reset */
+    if (!level) {
+        qemu_system_reset_request(SHUTDOWN_CAUSE_GUEST_RESET);
+    }
+}
+
 static void sifive_u_machine_init(MachineState *machine)
 {
     const struct MemmapEntry *memmap = sifive_u_memmap;
@@ -345,11 +399,41 @@ static void sifive_u_machine_init(MachineState *machine)
     memory_region_add_subregion(system_memory, memmap[SIFIVE_U_FLASH0].base,
                                 flash0);
 
+    /* register gpio-restart */
+    qdev_connect_gpio_out(DEVICE(&(s->soc.gpio)), 10,
+                          qemu_allocate_irq(sifive_u_machine_reset, NULL, 0));
+
     /* create device tree */
     create_fdt(s, memmap, machine->ram_size, machine->kernel_cmdline);
 
-    riscv_find_and_load_firmware(machine, BIOS_FILENAME,
-                                 memmap[SIFIVE_U_DRAM].base, NULL);
+    if (s->start_in_flash) {
+        /*
+         * If start_in_flash property is given, assign s->msel to a value
+         * that representing booting from QSPI0 memory-mapped flash.
+         *
+         * This also means that when both start_in_flash and msel properties
+         * are given, start_in_flash takes the precedence over msel.
+         *
+         * Note this is to keep backward compatibility not to break existing
+         * users that use start_in_flash property.
+         */
+        s->msel = MSEL_MEMMAP_QSPI0_FLASH;
+    }
+
+    switch (s->msel) {
+    case MSEL_MEMMAP_QSPI0_FLASH:
+        start_addr = memmap[SIFIVE_U_FLASH0].base;
+        break;
+    case MSEL_L2LIM_QSPI0_FLASH:
+    case MSEL_L2LIM_QSPI2_SD:
+        start_addr = memmap[SIFIVE_U_L2LIM].base;
+        break;
+    default:
+        start_addr = memmap[SIFIVE_U_DRAM].base;
+        break;
+    }
+
+    riscv_find_and_load_firmware(machine, BIOS_FILENAME, start_addr, NULL);
 
     if (machine->kernel_filename) {
         uint64_t kernel_entry = riscv_load_kernel(machine->kernel_filename,
@@ -367,24 +451,20 @@ static void sifive_u_machine_init(MachineState *machine)
         }
     }
 
-    if (s->start_in_flash) {
-        start_addr = memmap[SIFIVE_U_FLASH0].base;
-    }
-
     /* reset vector */
     uint32_t reset_vec[8] = {
+        s->msel,                       /* MSEL pin state */
         0x00000297,                    /* 1:  auipc  t0, %pcrel_hi(dtb) */
-        0x02028593,                    /*     addi   a1, t0, %pcrel_lo(1b) */
+        0x01c28593,                    /*     addi   a1, t0, %pcrel_lo(1b) */
         0xf1402573,                    /*     csrr   a0, mhartid  */
 #if defined(TARGET_RISCV32)
         0x0182a283,                    /*     lw     t0, 24(t0) */
 #elif defined(TARGET_RISCV64)
-        0x0182b283,                    /*     ld     t0, 24(t0) */
+        0x0182e283,                    /*     lwu    t0, 24(t0) */
 #endif
         0x00028067,                    /*     jr     t0 */
         0x00000000,
         start_addr,                    /* start: .dword */
-        0x00000000,
                                        /* dtb: */
     };
 
@@ -421,14 +501,16 @@ static void sifive_u_machine_set_start_in_flash(Object *obj, bool value, Error *
     s->start_in_flash = value;
 }
 
-static void sifive_u_machine_get_serial(Object *obj, Visitor *v, const char *name,
-                                void *opaque, Error **errp)
+static void sifive_u_machine_get_uint32_prop(Object *obj, Visitor *v,
+                                             const char *name, void *opaque,
+                                             Error **errp)
 {
     visit_type_uint32(v, name, (uint32_t *)opaque, errp);
 }
 
-static void sifive_u_machine_set_serial(Object *obj, Visitor *v, const char *name,
-                                void *opaque, Error **errp)
+static void sifive_u_machine_set_uint32_prop(Object *obj, Visitor *v,
+                                             const char *name, void *opaque,
+                                             Error **errp)
 {
     visit_type_uint32(v, name, (uint32_t *)opaque, errp);
 }
@@ -443,12 +525,20 @@ static void sifive_u_machine_instance_init(Object *obj)
                              sifive_u_machine_set_start_in_flash);
     object_property_set_description(obj, "start-in-flash",
                                     "Set on to tell QEMU's ROM to jump to "
-                                    "flash. Otherwise QEMU will jump to DRAM");
+                                    "flash. Otherwise QEMU will jump to DRAM "
+                                    "or L2LIM depending on the msel value");
+
+    s->msel = 0;
+    object_property_add(obj, "msel", "uint32",
+                        sifive_u_machine_get_uint32_prop,
+                        sifive_u_machine_set_uint32_prop, NULL, &s->msel);
+    object_property_set_description(obj, "msel",
+                                    "Mode Select (MSEL[3:0]) pin state");
 
     s->serial = OTP_SERIAL;
     object_property_add(obj, "serial", "uint32",
-                        sifive_u_machine_get_serial,
-                        sifive_u_machine_set_serial, NULL, &s->serial);
+                        sifive_u_machine_get_uint32_prop,
+                        sifive_u_machine_set_uint32_prop, NULL, &s->serial);
     object_property_set_description(obj, "serial", "Board serial number");
 }
 
@@ -504,6 +594,7 @@ static void sifive_u_soc_instance_init(Object *obj)
     object_initialize_child(obj, "prci", &s->prci, TYPE_SIFIVE_U_PRCI);
     object_initialize_child(obj, "otp", &s->otp, TYPE_SIFIVE_U_OTP);
     object_initialize_child(obj, "gem", &s->gem, TYPE_CADENCE_GEM);
+    object_initialize_child(obj, "gpio", &s->gpio, TYPE_SIFIVE_GPIO);
 }
 
 static void sifive_u_soc_realize(DeviceState *dev, Error **errp)
@@ -514,7 +605,6 @@ static void sifive_u_soc_realize(DeviceState *dev, Error **errp)
     MemoryRegion *system_memory = get_system_memory();
     MemoryRegion *mask_rom = g_new(MemoryRegion, 1);
     MemoryRegion *l2lim_mem = g_new(MemoryRegion, 1);
-    qemu_irq plic_gpios[SIFIVE_U_PLIC_NUM_SOURCES];
     char *plic_hart_config;
     size_t plic_hart_config_len;
     int i;
@@ -590,14 +680,24 @@ static void sifive_u_soc_realize(DeviceState *dev, Error **errp)
     sysbus_realize(SYS_BUS_DEVICE(&s->prci), &err);
     sysbus_mmio_map(SYS_BUS_DEVICE(&s->prci), 0, memmap[SIFIVE_U_PRCI].base);
 
+    qdev_prop_set_uint32(DEVICE(&s->gpio), "ngpio", 16);
+    sysbus_realize(SYS_BUS_DEVICE(&s->gpio), &err);
+    sysbus_mmio_map(SYS_BUS_DEVICE(&s->gpio), 0, memmap[SIFIVE_U_GPIO].base);
+
+    /* Pass all GPIOs to the SOC layer so they are available to the board */
+    qdev_pass_gpios(DEVICE(&s->gpio), dev, NULL);
+
+    /* Connect GPIO interrupts to the PLIC */
+    for (i = 0; i < 16; i++) {
+        sysbus_connect_irq(SYS_BUS_DEVICE(&s->gpio), i,
+                           qdev_get_gpio_in(DEVICE(s->plic),
+                                            SIFIVE_U_GPIO_IRQ0 + i));
+    }
+
     qdev_prop_set_uint32(DEVICE(&s->otp), "serial", s->serial);
     sysbus_realize(SYS_BUS_DEVICE(&s->otp), &err);
     sysbus_mmio_map(SYS_BUS_DEVICE(&s->otp), 0, memmap[SIFIVE_U_OTP].base);
 
-    for (i = 0; i < SIFIVE_U_PLIC_NUM_SOURCES; i++) {
-        plic_gpios[i] = qdev_get_gpio_in(DEVICE(s->plic), i);
-    }
-
     if (nd->used) {
         qemu_check_nic_model(nd, TYPE_CADENCE_GEM);
         qdev_set_nic_properties(DEVICE(&s->gem), nd);
@@ -611,10 +711,13 @@ static void sifive_u_soc_realize(DeviceState *dev, Error **errp)
     }
     sysbus_mmio_map(SYS_BUS_DEVICE(&s->gem), 0, memmap[SIFIVE_U_GEM].base);
     sysbus_connect_irq(SYS_BUS_DEVICE(&s->gem), 0,
-                       plic_gpios[SIFIVE_U_GEM_IRQ]);
+                       qdev_get_gpio_in(DEVICE(s->plic), SIFIVE_U_GEM_IRQ));
 
     create_unimplemented_device("riscv.sifive.u.gem-mgmt",
         memmap[SIFIVE_U_GEM_MGMT].base, memmap[SIFIVE_U_GEM_MGMT].size);
+
+    create_unimplemented_device("riscv.sifive.u.dmc",
+        memmap[SIFIVE_U_DMC].base, memmap[SIFIVE_U_DMC].size);
 }
 
 static Property sifive_u_soc_props[] = {