1 files changed, 289 insertions, 0 deletions
diff --git a/hw/char/sifive_uart.c b/hw/char/sifive_uart.c
new file mode 100644
index 000000000..1c75f792b
--- /dev/null
+++ b/hw/char/sifive_uart.c
@@ -0,0 +1,289 @@
+/*
+ * 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"
+
+/*
+ * 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 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 0; /* Should check tx fifo */
+    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;
+    unsigned char ch = value;
+
+    switch (addr) {
+    case SIFIVE_UART_TXFIFO:
+        qemu_chr_fe_write(&s->chr, &ch, 1);
+        sifive_uart_update_irq(s);
+        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 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 Property sifive_uart_properties[] = {
+    DEFINE_PROP_CHR("chardev", SiFiveUARTState, chr),
+    DEFINE_PROP_END_OF_LIST(),
+};
+
+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);
+
+    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->ie = 0;
+    s->ip = 0;
+    s->txctrl = 0;
+    s->rxctrl = 0;
+    s->div = 0;
+    s->rx_fifo_len = 0;
+}
+
+static void sifive_uart_reset_hold(Object *obj)
+{
+    SiFiveUARTState *s = SIFIVE_UART(obj);
+    qemu_irq_lower(s->irq);
+}
+
+static const VMStateDescription vmstate_sifive_uart = {
+    .name = TYPE_SIFIVE_UART,
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .fields = (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_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;
+    SiFiveUARTState *r;
+
+    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);
+
+    r = SIFIVE_UART(dev);
+    return r;
+}