hw/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.h"
  13 #include "sysbus.h"
  14 #include "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 typedef struct EmptySlot {
  26     SysBusDevice busdev;
  27     uint64_t size;
  28 } EmptySlot;
  29
  30 static uint32_t empty_slot_readl(void *opaque, target_phys_addr_t addr)
  31 {
  32     DPRINTF("read from " TARGET_FMT_plx "\n", addr);
  33     return 0;
  34 }
  35
  36 static void empty_slot_writel(void *opaque, target_phys_addr_t addr,
  37                               uint32_t val)
  38 {
  39     DPRINTF("write 0x%x to " TARGET_FMT_plx "\n", val, addr);
  40 }
  41
  42 CPUReadMemoryFunc * const empty_slot_read[3] = {
  43     empty_slot_readl,
  44     empty_slot_readl,
  45     empty_slot_readl,
  46 };
  47
  48 static CPUWriteMemoryFunc * const empty_slot_write[3] = {
  49     empty_slot_writel,
  50     empty_slot_writel,
  51     empty_slot_writel,
  52 };
  53
  54 void empty_slot_init(target_phys_addr_t 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, "empty_slot");
  63         s = sysbus_from_qdev(dev);
  64         e = FROM_SYSBUS(EmptySlot, s);
  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 = FROM_SYSBUS(EmptySlot, dev);
  76     ram_addr_t empty_slot_offset;
  77
  78     empty_slot_offset = cpu_register_io_memory(empty_slot_read,
  79                                                empty_slot_write, s,
  80                                                DEVICE_NATIVE_ENDIAN);
  81     sysbus_init_mmio(dev, s->size, empty_slot_offset | IO_MEM_RAM);
  82     return 0;
  83 }
  84
  85 static SysBusDeviceInfo empty_slot_info = {
  86     .init = empty_slot_init1,
  87     .qdev.name  = "empty_slot",
  88     .qdev.size  = sizeof(EmptySlot),
  89 };
  90
  91 static void empty_slot_register_devices(void)
  92 {
  93     sysbus_register_withprop(&empty_slot_info);
  94 }
  95
  96 device_init(empty_slot_register_devices);