hw/core/empty_slot.c

   1 /*
   2  * QEMU Empty Slot
   3  *
   4  * The empty_slot device emulates known to a bus but not connected devices.
   5  *
   6  * Copyright (c) 2010 Artyom Tarasenko
   7  *
   8  * This code is licensed under the GNU GPL v2 or (at your option) any later
   9  * version.
  10  */
  11
  12 #include "hw/hw.h"
  13 #include "hw/sysbus.h"
  14 #include "hw/empty_slot.h"
  15
  16 //#define DEBUG_EMPTY_SLOT
  17
  18 #ifdef DEBUG_EMPTY_SLOT
  19 #define DPRINTF(fmt, ...)                                       \
  20     do { printf("empty_slot: " fmt , ## __VA_ARGS__); } while (0)
  21 #else
  22 #define DPRINTF(fmt, ...) do {} while (0)
  23 #endif
  24
  25 #define TYPE_EMPTY_SLOT "empty_slot"
  26 #define EMPTY_SLOT(obj) OBJECT_CHECK(EmptySlot, (obj), TYPE_EMPTY_SLOT)
  27
  28 typedef struct EmptySlot {
  29     SysBusDevice parent_obj;
  30
  31     MemoryRegion iomem;
  32     uint64_t size;
  33 } EmptySlot;
  34
  35 static uint64_t empty_slot_read(void *opaque, hwaddr addr,
  36                                 unsigned size)
  37 {
  38     DPRINTF("read from " TARGET_FMT_plx "\n", addr);
  39     return 0;
  40 }
  41
  42 static void empty_slot_write(void *opaque, hwaddr addr,
  43                              uint64_t val, unsigned size)
  44 {
  45     DPRINTF("write 0x%x to " TARGET_FMT_plx "\n", (unsigned)val, addr);
  46 }
  47
  48 static const MemoryRegionOps empty_slot_ops = {
  49     .read = empty_slot_read,
  50     .write = empty_slot_write,
  51     .endianness = DEVICE_NATIVE_ENDIAN,
  52 };
  53
  54 void empty_slot_init(hwaddr addr, uint64_t slot_size)
  55 {
  56     if (slot_size > 0) {
  57         /* Only empty slots larger than 0 byte need handling. */
  58         DeviceState *dev;
  59         SysBusDevice *s;
  60         EmptySlot *e;
  61
  62         dev = qdev_create(NULL, TYPE_EMPTY_SLOT);
  63         s = SYS_BUS_DEVICE(dev);
  64         e = EMPTY_SLOT(dev);
  65         e->size = slot_size;
  66
  67         qdev_init_nofail(dev);
  68
  69         sysbus_mmio_map(s, 0, addr);
  70     }
  71 }
  72
  73 static int empty_slot_init1(SysBusDevice *dev)
  74 {
  75     EmptySlot *s = EMPTY_SLOT(dev);
  76
  77     memory_region_init_io(&s->iomem, OBJECT(s), &empty_slot_ops, s,
  78                           "empty-slot", s->size);
  79     sysbus_init_mmio(dev, &s->iomem);
  80     return 0;
  81 }
  82
  83 static void empty_slot_class_init(ObjectClass *klass, void *data)
  84 {
  85     SysBusDeviceClass *k = SYS_BUS_DEVICE_CLASS(klass);
  86
  87     k->init = empty_slot_init1;
  88 }
  89
  90 static const TypeInfo empty_slot_info = {
  91     .name          = TYPE_EMPTY_SLOT,
  92     .parent        = TYPE_SYS_BUS_DEVICE,
  93     .instance_size = sizeof(EmptySlot),
  94     .class_init    = empty_slot_class_init,
  95 };
  96
  97 static void empty_slot_register_types(void)
  98 {
  99     type_register_static(&empty_slot_info);
 100 }
 101
 102 type_init(empty_slot_register_types)