create empty_slot device

The empty_slot device emulates known to a bus but not connected devices.
Signed-off-by: NArtyom Tarasenko <atar4qemu@gmail.com>
Signed-off-by: NBlue Swirl <blauwirbel@gmail.com>

hw/empty_slot.c

+/*
+ * 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.h"
+#include "sysbus.h"
+#include "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;
+    uint64_t size;
+} EmptySlot;
+
+static uint32_t empty_slot_readl(void *opaque, target_phys_addr_t addr)
+{
+    DPRINTF("read from " TARGET_FMT_plx "\n", addr);
+    return 0;
+}
+
+static void empty_slot_writel(void *opaque, target_phys_addr_t addr,
+                              uint32_t val)
+{
+    DPRINTF("write 0x%x to " TARGET_FMT_plx "\n", val, addr);
+}
+
+CPUReadMemoryFunc * const empty_slot_read[3] = {
+    empty_slot_readl,
+    empty_slot_readl,
+    empty_slot_readl,
+};
+
+static CPUWriteMemoryFunc * const empty_slot_write[3] = {
+    empty_slot_writel,
+    empty_slot_writel,
+    empty_slot_writel,
+};
+
+void empty_slot_init(target_phys_addr_t addr, uint64_t slot_size)
+{
+    DeviceState *dev;
+    SysBusDevice *s;
+    EmptySlot *e;
+
+    dev = qdev_create(NULL, "empty_slot");
+    s = sysbus_from_qdev(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);
+    ram_addr_t empty_slot_offset;
+
+    empty_slot_offset = cpu_register_io_memory(empty_slot_read,
+                                               empty_slot_write, s);
+    sysbus_init_mmio(dev, s->size, empty_slot_offset | IO_MEM_RAM);
+    return 0;
+}
+
+static SysBusDeviceInfo empty_slot_info = {
+    .init = empty_slot_init1,
+    .qdev.name  = "empty_slot",
+    .qdev.size  = sizeof(EmptySlot),
+};
+
+static void empty_slot_register_devices(void)
+{
+    sysbus_register_withprop(&empty_slot_info);
+}
+
+device_init(empty_slot_register_devices);

hw/empty_slot.h

+/* empty_slot.c */
+void empty_slot_init(target_phys_addr_t addr, uint64_t slot_size);