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/hw.h"
  14 #include "hw/sysbus.h"
  15 #include "qemu/module.h"
  16 #include "hw/empty_slot.h"
  17
  18 //#define DEBUG_EMPTY_SLOT
  19
  20 #ifdef DEBUG_EMPTY_SLOT
  21 #define DPRINTF(fmt, ...)                                       \
  22     do { printf("empty_slot: " fmt , ## __VA_ARGS__); } while (0)
  23 #else
  24 #define DPRINTF(fmt, ...) do {} while (0)
  25 #endif
  26
  27 #define TYPE_EMPTY_SLOT "empty_slot"
  28 #define EMPTY_SLOT(obj) OBJECT_CHECK(EmptySlot, (obj), TYPE_EMPTY_SLOT)
  29
  30 typedef struct EmptySlot {
  31     SysBusDevice parent_obj;
  32
  33     MemoryRegion iomem;
  34     uint64_t size;
  35 } EmptySlot;
  36
  37 static uint64_t empty_slot_read(void *opaque, hwaddr addr,
  38                                 unsigned size)
  39 {
  40     DPRINTF("read from " TARGET_FMT_plx "\n", addr);
  41     return 0;
  42 }
  43
  44 static void empty_slot_write(void *opaque, hwaddr addr,
  45                              uint64_t val, unsigned size)
  46 {
  47     DPRINTF("write 0x%x to " TARGET_FMT_plx "\n", (unsigned)val, addr);
  48 }
  49
  50 static const MemoryRegionOps empty_slot_ops = {
  51     .read = empty_slot_read,
  52     .write = empty_slot_write,
  53     .endianness = DEVICE_NATIVE_ENDIAN,
  54 };
  55
  56 void empty_slot_init(hwaddr addr, uint64_t slot_size)
  57 {
  58     if (slot_size > 0) {
  59         /* Only empty slots larger than 0 byte need handling. */
  60         DeviceState *dev;
  61         SysBusDevice *s;
  62         EmptySlot *e;
  63
  64         dev = qdev_create(NULL, TYPE_EMPTY_SLOT);
  65         s = SYS_BUS_DEVICE(dev);
  66         e = EMPTY_SLOT(dev);
  67         e->size = slot_size;
  68
  69         qdev_init_nofail(dev);
  70
  71         sysbus_mmio_map(s, 0, addr);
  72     }
  73 }
  74
  75 static void empty_slot_realize(DeviceState *dev, Error **errp)
  76 {
  77     EmptySlot *s = EMPTY_SLOT(dev);
  78
  79     memory_region_init_io(&s->iomem, OBJECT(s), &empty_slot_ops, s,
  80                           "empty-slot", s->size);
  81     sysbus_init_mmio(SYS_BUS_DEVICE(dev), &s->iomem);
  82 }
  83
  84 static void empty_slot_class_init(ObjectClass *klass, void *data)
  85 {
  86     DeviceClass *dc = DEVICE_CLASS(klass);
  87
  88     dc->realize = empty_slot_realize;
  89 }
  90
  91 static const TypeInfo empty_slot_info = {
  92     .name          = TYPE_EMPTY_SLOT,
  93     .parent        = TYPE_SYS_BUS_DEVICE,
  94     .instance_size = sizeof(EmptySlot),
  95     .class_init    = empty_slot_class_init,
  96 };
  97
  98 static void empty_slot_register_types(void)
  99 {
 100     type_register_static(&empty_slot_info);
 101 }
 102
 103 type_init(empty_slot_register_types)