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, 146 insertions, 0 deletions

diff --git a/hw/ssi/ssi.c b/hw/ssi/ssi.c
new file mode 100644
index 000000000..003931fb5
--- /dev/null
+++ b/hw/ssi/ssi.c
@@ -0,0 +1,146 @@
+/*
+ * QEMU Synchronous Serial Interface support
+ *
+ * Copyright (c) 2009 CodeSourcery.
+ * Copyright (c) 2012 Peter A.G. Crosthwaite (peter.crosthwaite@petalogix.com)
+ * Copyright (c) 2012 PetaLogix Pty Ltd.
+ * Written by Paul Brook
+ *
+ * This code is licensed under the GNU GPL v2.
+ *
+ * Contributions after 2012-01-13 are licensed under the terms of the
+ * GNU GPL, version 2 or (at your option) any later version.
+ */
+
+#include "qemu/osdep.h"
+#include "hw/ssi/ssi.h"
+#include "migration/vmstate.h"
+#include "qemu/module.h"
+#include "qapi/error.h"
+#include "qom/object.h"
+
+struct SSIBus {
+    BusState parent_obj;
+};
+
+#define TYPE_SSI_BUS "SSI"
+OBJECT_DECLARE_SIMPLE_TYPE(SSIBus, SSI_BUS)
+
+static const TypeInfo ssi_bus_info = {
+    .name = TYPE_SSI_BUS,
+    .parent = TYPE_BUS,
+    .instance_size = sizeof(SSIBus),
+};
+
+static void ssi_cs_default(void *opaque, int n, int level)
+{
+    SSIPeripheral *s = SSI_PERIPHERAL(opaque);
+    bool cs = !!level;
+    assert(n == 0);
+    if (s->cs != cs) {
+        SSIPeripheralClass *ssc = SSI_PERIPHERAL_GET_CLASS(s);
+        if (ssc->set_cs) {
+            ssc->set_cs(s, cs);
+        }
+    }
+    s->cs = cs;
+}
+
+static uint32_t ssi_transfer_raw_default(SSIPeripheral *dev, uint32_t val)
+{
+    SSIPeripheralClass *ssc = SSI_PERIPHERAL_GET_CLASS(dev);
+
+    if ((dev->cs && ssc->cs_polarity == SSI_CS_HIGH) ||
+            (!dev->cs && ssc->cs_polarity == SSI_CS_LOW) ||
+            ssc->cs_polarity == SSI_CS_NONE) {
+        return ssc->transfer(dev, val);
+    }
+    return 0;
+}
+
+static void ssi_peripheral_realize(DeviceState *dev, Error **errp)
+{
+    SSIPeripheral *s = SSI_PERIPHERAL(dev);
+    SSIPeripheralClass *ssc = SSI_PERIPHERAL_GET_CLASS(s);
+
+    if (ssc->transfer_raw == ssi_transfer_raw_default &&
+            ssc->cs_polarity != SSI_CS_NONE) {
+        qdev_init_gpio_in_named(dev, ssi_cs_default, SSI_GPIO_CS, 1);
+    }
+
+    ssc->realize(s, errp);
+}
+
+static void ssi_peripheral_class_init(ObjectClass *klass, void *data)
+{
+    SSIPeripheralClass *ssc = SSI_PERIPHERAL_CLASS(klass);
+    DeviceClass *dc = DEVICE_CLASS(klass);
+
+    dc->realize = ssi_peripheral_realize;
+    dc->bus_type = TYPE_SSI_BUS;
+    if (!ssc->transfer_raw) {
+        ssc->transfer_raw = ssi_transfer_raw_default;
+    }
+}
+
+static const TypeInfo ssi_peripheral_info = {
+    .name = TYPE_SSI_PERIPHERAL,
+    .parent = TYPE_DEVICE,
+    .class_init = ssi_peripheral_class_init,
+    .class_size = sizeof(SSIPeripheralClass),
+    .abstract = true,
+};
+
+bool ssi_realize_and_unref(DeviceState *dev, SSIBus *bus, Error **errp)
+{
+    return qdev_realize_and_unref(dev, &bus->parent_obj, errp);
+}
+
+DeviceState *ssi_create_peripheral(SSIBus *bus, const char *name)
+{
+    DeviceState *dev = qdev_new(name);
+
+    ssi_realize_and_unref(dev, bus, &error_fatal);
+    return dev;
+}
+
+SSIBus *ssi_create_bus(DeviceState *parent, const char *name)
+{
+    BusState *bus;
+    bus = qbus_new(TYPE_SSI_BUS, parent, name);
+    return SSI_BUS(bus);
+}
+
+uint32_t ssi_transfer(SSIBus *bus, uint32_t val)
+{
+    BusState *b = BUS(bus);
+    BusChild *kid;
+    SSIPeripheralClass *ssc;
+    uint32_t r = 0;
+
+    QTAILQ_FOREACH(kid, &b->children, sibling) {
+        SSIPeripheral *peripheral = SSI_PERIPHERAL(kid->child);
+        ssc = SSI_PERIPHERAL_GET_CLASS(peripheral);
+        r |= ssc->transfer_raw(peripheral, val);
+    }
+
+    return r;
+}
+
+const VMStateDescription vmstate_ssi_peripheral = {
+    .name = "SSISlave",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .fields = (VMStateField[]) {
+        VMSTATE_BOOL(cs, SSIPeripheral),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
+static void ssi_peripheral_register_types(void)
+{
+    type_register_static(&ssi_bus_info);
+    type_register_static(&ssi_peripheral_info);
+}
+
+type_init(ssi_peripheral_register_types)