Introduce Virtio-loopback epsilon release:

Epsilon release introduces a new compatibility layer which make virtio-loopback
design to work with QEMU and rust-vmm vhost-user backend without require any
changes.

Signed-off-by: Timos Ampelikiotis <t.ampelikiotis@virtualopensystems.com>
Change-Id: I52e57563e08a7d0bdc002f8e928ee61ba0c53dd9

1 files changed, 366 insertions, 0 deletions

diff --git a/hw/char/mcf_uart.c b/hw/char/mcf_uart.c
new file mode 100644
index 000000000..6fa4ac502
--- /dev/null
+++ b/hw/char/mcf_uart.c
@@ -0,0 +1,366 @@
+/*
+ * ColdFire UART emulation.
+ *
+ * Copyright (c) 2007 CodeSourcery.
+ *
+ * This code is licensed under the GPL
+ */
+
+#include "qemu/osdep.h"
+#include "hw/irq.h"
+#include "hw/sysbus.h"
+#include "qemu/module.h"
+#include "qapi/error.h"
+#include "hw/m68k/mcf.h"
+#include "hw/qdev-properties.h"
+#include "hw/qdev-properties-system.h"
+#include "chardev/char-fe.h"
+#include "qom/object.h"
+
+struct mcf_uart_state {
+    SysBusDevice parent_obj;
+
+    MemoryRegion iomem;
+    uint8_t mr[2];
+    uint8_t sr;
+    uint8_t isr;
+    uint8_t imr;
+    uint8_t bg1;
+    uint8_t bg2;
+    uint8_t fifo[4];
+    uint8_t tb;
+    int current_mr;
+    int fifo_len;
+    int tx_enabled;
+    int rx_enabled;
+    qemu_irq irq;
+    CharBackend chr;
+};
+
+#define TYPE_MCF_UART "mcf-uart"
+OBJECT_DECLARE_SIMPLE_TYPE(mcf_uart_state, MCF_UART)
+
+/* UART Status Register bits.  */
+#define MCF_UART_RxRDY  0x01
+#define MCF_UART_FFULL  0x02
+#define MCF_UART_TxRDY  0x04
+#define MCF_UART_TxEMP  0x08
+#define MCF_UART_OE     0x10
+#define MCF_UART_PE     0x20
+#define MCF_UART_FE     0x40
+#define MCF_UART_RB     0x80
+
+/* Interrupt flags.  */
+#define MCF_UART_TxINT  0x01
+#define MCF_UART_RxINT  0x02
+#define MCF_UART_DBINT  0x04
+#define MCF_UART_COSINT 0x80
+
+/* UMR1 flags.  */
+#define MCF_UART_BC0    0x01
+#define MCF_UART_BC1    0x02
+#define MCF_UART_PT     0x04
+#define MCF_UART_PM0    0x08
+#define MCF_UART_PM1    0x10
+#define MCF_UART_ERR    0x20
+#define MCF_UART_RxIRQ  0x40
+#define MCF_UART_RxRTS  0x80
+
+static void mcf_uart_update(mcf_uart_state *s)
+{
+    s->isr &= ~(MCF_UART_TxINT | MCF_UART_RxINT);
+    if (s->sr & MCF_UART_TxRDY)
+        s->isr |= MCF_UART_TxINT;
+    if ((s->sr & ((s->mr[0] & MCF_UART_RxIRQ)
+                  ? MCF_UART_FFULL : MCF_UART_RxRDY)) != 0)
+        s->isr |= MCF_UART_RxINT;
+
+    qemu_set_irq(s->irq, (s->isr & s->imr) != 0);
+}
+
+uint64_t mcf_uart_read(void *opaque, hwaddr addr,
+                       unsigned size)
+{
+    mcf_uart_state *s = (mcf_uart_state *)opaque;
+    switch (addr & 0x3f) {
+    case 0x00:
+        return s->mr[s->current_mr];
+    case 0x04:
+        return s->sr;
+    case 0x0c:
+        {
+            uint8_t val;
+            int i;
+
+            if (s->fifo_len == 0)
+                return 0;
+
+            val = s->fifo[0];
+            s->fifo_len--;
+            for (i = 0; i < s->fifo_len; i++)
+                s->fifo[i] = s->fifo[i + 1];
+            s->sr &= ~MCF_UART_FFULL;
+            if (s->fifo_len == 0)
+                s->sr &= ~MCF_UART_RxRDY;
+            mcf_uart_update(s);
+            qemu_chr_fe_accept_input(&s->chr);
+            return val;
+        }
+    case 0x10:
+        /* TODO: Implement IPCR.  */
+        return 0;
+    case 0x14:
+        return s->isr;
+    case 0x18:
+        return s->bg1;
+    case 0x1c:
+        return s->bg2;
+    default:
+        return 0;
+    }
+}
+
+/* Update TxRDY flag and set data if present and enabled.  */
+static void mcf_uart_do_tx(mcf_uart_state *s)
+{
+    if (s->tx_enabled && (s->sr & MCF_UART_TxEMP) == 0) {
+        /* XXX this blocks entire thread. Rewrite to use
+         * qemu_chr_fe_write and background I/O callbacks */
+        qemu_chr_fe_write_all(&s->chr, (unsigned char *)&s->tb, 1);
+        s->sr |= MCF_UART_TxEMP;
+    }
+    if (s->tx_enabled) {
+        s->sr |= MCF_UART_TxRDY;
+    } else {
+        s->sr &= ~MCF_UART_TxRDY;
+    }
+}
+
+static void mcf_do_command(mcf_uart_state *s, uint8_t cmd)
+{
+    /* Misc command.  */
+    switch ((cmd >> 4) & 7) {
+    case 0: /* No-op.  */
+        break;
+    case 1: /* Reset mode register pointer.  */
+        s->current_mr = 0;
+        break;
+    case 2: /* Reset receiver.  */
+        s->rx_enabled = 0;
+        s->fifo_len = 0;
+        s->sr &= ~(MCF_UART_RxRDY | MCF_UART_FFULL);
+        break;
+    case 3: /* Reset transmitter.  */
+        s->tx_enabled = 0;
+        s->sr |= MCF_UART_TxEMP;
+        s->sr &= ~MCF_UART_TxRDY;
+        break;
+    case 4: /* Reset error status.  */
+        break;
+    case 5: /* Reset break-change interrupt.  */
+        s->isr &= ~MCF_UART_DBINT;
+        break;
+    case 6: /* Start break.  */
+    case 7: /* Stop break.  */
+        break;
+    }
+
+    /* Transmitter command.  */
+    switch ((cmd >> 2) & 3) {
+    case 0: /* No-op.  */
+        break;
+    case 1: /* Enable.  */
+        s->tx_enabled = 1;
+        mcf_uart_do_tx(s);
+        break;
+    case 2: /* Disable.  */
+        s->tx_enabled = 0;
+        mcf_uart_do_tx(s);
+        break;
+    case 3: /* Reserved.  */
+        fprintf(stderr, "mcf_uart: Bad TX command\n");
+        break;
+    }
+
+    /* Receiver command.  */
+    switch (cmd & 3) {
+    case 0: /* No-op.  */
+        break;
+    case 1: /* Enable.  */
+        s->rx_enabled = 1;
+        break;
+    case 2:
+        s->rx_enabled = 0;
+        break;
+    case 3: /* Reserved.  */
+        fprintf(stderr, "mcf_uart: Bad RX command\n");
+        break;
+    }
+}
+
+void mcf_uart_write(void *opaque, hwaddr addr,
+                    uint64_t val, unsigned size)
+{
+    mcf_uart_state *s = (mcf_uart_state *)opaque;
+    switch (addr & 0x3f) {
+    case 0x00:
+        s->mr[s->current_mr] = val;
+        s->current_mr = 1;
+        break;
+    case 0x04:
+        /* CSR is ignored.  */
+        break;
+    case 0x08: /* Command Register.  */
+        mcf_do_command(s, val);
+        break;
+    case 0x0c: /* Transmit Buffer.  */
+        s->sr &= ~MCF_UART_TxEMP;
+        s->tb = val;
+        mcf_uart_do_tx(s);
+        break;
+    case 0x10:
+        /* ACR is ignored.  */
+        break;
+    case 0x14:
+        s->imr = val;
+        break;
+    default:
+        break;
+    }
+    mcf_uart_update(s);
+}
+
+static void mcf_uart_reset(DeviceState *dev)
+{
+    mcf_uart_state *s = MCF_UART(dev);
+
+    s->fifo_len = 0;
+    s->mr[0] = 0;
+    s->mr[1] = 0;
+    s->sr = MCF_UART_TxEMP;
+    s->tx_enabled = 0;
+    s->rx_enabled = 0;
+    s->isr = 0;
+    s->imr = 0;
+}
+
+static void mcf_uart_push_byte(mcf_uart_state *s, uint8_t data)
+{
+    /* Break events overwrite the last byte if the fifo is full.  */
+    if (s->fifo_len == 4)
+        s->fifo_len--;
+
+    s->fifo[s->fifo_len] = data;
+    s->fifo_len++;
+    s->sr |= MCF_UART_RxRDY;
+    if (s->fifo_len == 4)
+        s->sr |= MCF_UART_FFULL;
+
+    mcf_uart_update(s);
+}
+
+static void mcf_uart_event(void *opaque, QEMUChrEvent event)
+{
+    mcf_uart_state *s = (mcf_uart_state *)opaque;
+
+    switch (event) {
+    case CHR_EVENT_BREAK:
+        s->isr |= MCF_UART_DBINT;
+        mcf_uart_push_byte(s, 0);
+        break;
+    default:
+        break;
+    }
+}
+
+static int mcf_uart_can_receive(void *opaque)
+{
+    mcf_uart_state *s = (mcf_uart_state *)opaque;
+
+    return s->rx_enabled && (s->sr & MCF_UART_FFULL) == 0;
+}
+
+static void mcf_uart_receive(void *opaque, const uint8_t *buf, int size)
+{
+    mcf_uart_state *s = (mcf_uart_state *)opaque;
+
+    mcf_uart_push_byte(s, buf[0]);
+}
+
+static const MemoryRegionOps mcf_uart_ops = {
+    .read = mcf_uart_read,
+    .write = mcf_uart_write,
+    .endianness = DEVICE_NATIVE_ENDIAN,
+};
+
+static void mcf_uart_instance_init(Object *obj)
+{
+    SysBusDevice *dev = SYS_BUS_DEVICE(obj);
+    mcf_uart_state *s = MCF_UART(dev);
+
+    memory_region_init_io(&s->iomem, obj, &mcf_uart_ops, s, "uart", 0x40);
+    sysbus_init_mmio(dev, &s->iomem);
+
+    sysbus_init_irq(dev, &s->irq);
+}
+
+static void mcf_uart_realize(DeviceState *dev, Error **errp)
+{
+    mcf_uart_state *s = MCF_UART(dev);
+
+    qemu_chr_fe_set_handlers(&s->chr, mcf_uart_can_receive, mcf_uart_receive,
+                             mcf_uart_event, NULL, s, NULL, true);
+}
+
+static Property mcf_uart_properties[] = {
+    DEFINE_PROP_CHR("chardev", mcf_uart_state, chr),
+    DEFINE_PROP_END_OF_LIST(),
+};
+
+static void mcf_uart_class_init(ObjectClass *oc, void *data)
+{
+    DeviceClass *dc = DEVICE_CLASS(oc);
+
+    dc->realize = mcf_uart_realize;
+    dc->reset = mcf_uart_reset;
+    device_class_set_props(dc, mcf_uart_properties);
+    set_bit(DEVICE_CATEGORY_INPUT, dc->categories);
+}
+
+static const TypeInfo mcf_uart_info = {
+    .name          = TYPE_MCF_UART,
+    .parent        = TYPE_SYS_BUS_DEVICE,
+    .instance_size = sizeof(mcf_uart_state),
+    .instance_init = mcf_uart_instance_init,
+    .class_init    = mcf_uart_class_init,
+};
+
+static void mcf_uart_register(void)
+{
+    type_register_static(&mcf_uart_info);
+}
+
+type_init(mcf_uart_register)
+
+void *mcf_uart_init(qemu_irq irq, Chardev *chrdrv)
+{
+    DeviceState  *dev;
+
+    dev = qdev_new(TYPE_MCF_UART);
+    if (chrdrv) {
+        qdev_prop_set_chr(dev, "chardev", chrdrv);
+    }
+    sysbus_realize_and_unref(SYS_BUS_DEVICE(dev), &error_fatal);
+
+    sysbus_connect_irq(SYS_BUS_DEVICE(dev), 0, irq);
+
+    return dev;
+}
+
+void mcf_uart_mm_init(hwaddr base, qemu_irq irq, Chardev *chrdrv)
+{
+    DeviceState  *dev;
+
+    dev = mcf_uart_init(irq, chrdrv);
+    sysbus_mmio_map(SYS_BUS_DEVICE(dev), 0, base);
+}