1 files changed, 98 insertions, 0 deletions
diff --git a/hw/core/empty_slot.c b/hw/core/empty_slot.c
new file mode 100644
index 0000000000..5234a4ddc6
--- /dev/null
+++ b/hw/core/empty_slot.c
@@ -0,0 +1,98 @@
+/*
+ * QEMU Empty Slot
+ *
+ * The empty_slot device emulates known to a bus but not connected devices.
+ *
+ * Copyright (c) 2010 Artyom Tarasenko
+ *
+ * This code is licensed under the GNU GPL v2 or (at your option) any later
+ * version.
+ */
+
+#include "hw/hw.h"
+#include "hw/sysbus.h"
+#include "hw/empty_slot.h"
+
+//#define DEBUG_EMPTY_SLOT
+
+#ifdef DEBUG_EMPTY_SLOT
+#define DPRINTF(fmt, ...)                                       \
+    do { printf("empty_slot: " fmt , ## __VA_ARGS__); } while (0)
+#else
+#define DPRINTF(fmt, ...) do {} while (0)
+#endif
+
+typedef struct EmptySlot {
+    SysBusDevice busdev;
+    MemoryRegion iomem;
+    uint64_t size;
+} EmptySlot;
+
+static uint64_t empty_slot_read(void *opaque, hwaddr addr,
+                                unsigned size)
+{
+    DPRINTF("read from " TARGET_FMT_plx "\n", addr);
+    return 0;
+}
+
+static void empty_slot_write(void *opaque, hwaddr addr,
+                             uint64_t val, unsigned size)
+{
+    DPRINTF("write 0x%x to " TARGET_FMT_plx "\n", (unsigned)val, addr);
+}
+
+static const MemoryRegionOps empty_slot_ops = {
+    .read = empty_slot_read,
+    .write = empty_slot_write,
+    .endianness = DEVICE_NATIVE_ENDIAN,
+};
+
+void empty_slot_init(hwaddr addr, uint64_t slot_size)
+{
+    if (slot_size > 0) {
+        /* Only empty slots larger than 0 byte need handling. */
+        DeviceState *dev;
+        SysBusDevice *s;
+        EmptySlot *e;
+
+        dev = qdev_create(NULL, "empty_slot");
+        s = SYS_BUS_DEVICE(dev);
+        e = FROM_SYSBUS(EmptySlot, s);
+        e->size = slot_size;
+
+        qdev_init_nofail(dev);
+
+        sysbus_mmio_map(s, 0, addr);
+    }
+}
+
+static int empty_slot_init1(SysBusDevice *dev)
+{
+    EmptySlot *s = FROM_SYSBUS(EmptySlot, dev);
+
+    memory_region_init_io(&s->iomem, &empty_slot_ops, s,
+                          "empty-slot", s->size);
+    sysbus_init_mmio(dev, &s->iomem);
+    return 0;
+}
+
+static void empty_slot_class_init(ObjectClass *klass, void *data)
+{
+    SysBusDeviceClass *k = SYS_BUS_DEVICE_CLASS(klass);
+
+    k->init = empty_slot_init1;
+}
+
+static const TypeInfo empty_slot_info = {
+    .name          = "empty_slot",
+    .parent        = TYPE_SYS_BUS_DEVICE,
+    .instance_size = sizeof(EmptySlot),
+    .class_init    = empty_slot_class_init,
+};
+
+static void empty_slot_register_types(void)
+{
+    type_register_static(&empty_slot_info);
+}
+
+type_init(empty_slot_register_types)