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 "qemu/osdep.h"
  13 #include "hw/sysbus.h"
  14 #include "qemu/module.h"
  15 #include "hw/empty_slot.h"
  16
  17 //#define DEBUG_EMPTY_SLOT
  18
  19 #ifdef DEBUG_EMPTY_SLOT
  20 #define DPRINTF(fmt, ...)                                       \
  21     do { printf("empty_slot: " fmt , ## __VA_ARGS__); } while (0)
  22 #else
  23 #define DPRINTF(fmt, ...) do {} while (0)
  24 #endif
  25
  26 #define TYPE_EMPTY_SLOT "empty_slot"
  27 #define EMPTY_SLOT(obj) OBJECT_CHECK(EmptySlot, (obj), TYPE_EMPTY_SLOT)
  28
  29 typedef struct EmptySlot {
  30     SysBusDevice parent_obj;
  31
  32     MemoryRegion iomem;
  33     uint64_t size;
  34 } EmptySlot;
  35
  36 static uint64_t empty_slot_read(void *opaque, hwaddr addr,
  37                                 unsigned size)
  38 {
  39     DPRINTF("read from " TARGET_FMT_plx "\n", addr);
  40     return 0;
  41 }
  42
  43 static void empty_slot_write(void *opaque, hwaddr addr,
  44                              uint64_t val, unsigned size)
  45 {
  46     DPRINTF("write 0x%x to " TARGET_FMT_plx "\n", (unsigned)val, addr);
  47 }
  48
  49 static const MemoryRegionOps empty_slot_ops = {
  50     .read = empty_slot_read,
  51     .write = empty_slot_write,
  52     .endianness = DEVICE_NATIVE_ENDIAN,
  53 };
  54
  55 void empty_slot_init(hwaddr addr, uint64_t slot_size)
  56 {
  57     if (slot_size > 0) {
  58         /* Only empty slots larger than 0 byte need handling. */
  59         DeviceState *dev;
  60         SysBusDevice *s;
  61         EmptySlot *e;
  62
  63         dev = qdev_create(NULL, TYPE_EMPTY_SLOT);
  64         s = SYS_BUS_DEVICE(dev);
  65         e = EMPTY_SLOT(dev);
  66         e->size = slot_size;
  67
  68         qdev_init_nofail(dev);
  69
  70         sysbus_mmio_map(s, 0, addr);
  71     }
  72 }
  73
  74 static void empty_slot_realize(DeviceState *dev, Error **errp)
  75 {
  76     EmptySlot *s = EMPTY_SLOT(dev);
  77
  78     memory_region_init_io(&s->iomem, OBJECT(s), &empty_slot_ops, s,
  79                           "empty-slot", s->size);
  80     sysbus_init_mmio(SYS_BUS_DEVICE(dev), &s->iomem);
  81 }
  82
  83 static void empty_slot_class_init(ObjectClass *klass, void *data)
  84 {
  85     DeviceClass *dc = DEVICE_CLASS(klass);
  86
  87     dc->realize = empty_slot_realize;
  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)