xref: /openbmc/qemu/hw/misc/empty_slot.c (revision b91a0fa7)
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 "hw/qdev-properties.h"
15 #include "hw/misc/empty_slot.h"
16 #include "qapi/error.h"
17 #include "trace.h"
18 #include "qom/object.h"
19 
20 #define TYPE_EMPTY_SLOT "empty_slot"
21 OBJECT_DECLARE_SIMPLE_TYPE(EmptySlot, EMPTY_SLOT)
22 
23 struct EmptySlot {
24     SysBusDevice parent_obj;
25 
26     MemoryRegion iomem;
27     char *name;
28     uint64_t size;
29 };
30 
31 static uint64_t empty_slot_read(void *opaque, hwaddr addr,
32                                 unsigned size)
33 {
34     EmptySlot *s = EMPTY_SLOT(opaque);
35 
36     trace_empty_slot_write(addr, size << 1, 0, size, s->name);
37 
38     return 0;
39 }
40 
41 static void empty_slot_write(void *opaque, hwaddr addr,
42                              uint64_t val, unsigned size)
43 {
44     EmptySlot *s = EMPTY_SLOT(opaque);
45 
46     trace_empty_slot_write(addr, size << 1, val, size, s->name);
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(const char *name, 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 
61         dev = qdev_new(TYPE_EMPTY_SLOT);
62 
63         qdev_prop_set_uint64(dev, "size", slot_size);
64         sysbus_realize_and_unref(SYS_BUS_DEVICE(dev), &error_fatal);
65 
66         sysbus_mmio_map_overlap(SYS_BUS_DEVICE(dev), 0, addr, -10000);
67     }
68 }
69 
70 static void empty_slot_realize(DeviceState *dev, Error **errp)
71 {
72     EmptySlot *s = EMPTY_SLOT(dev);
73 
74     if (s->name == NULL) {
75         s->name = g_strdup("empty-slot");
76     }
77     memory_region_init_io(&s->iomem, OBJECT(s), &empty_slot_ops, s,
78                           s->name, s->size);
79     sysbus_init_mmio(SYS_BUS_DEVICE(dev), &s->iomem);
80 }
81 
82 static Property empty_slot_properties[] = {
83     DEFINE_PROP_UINT64("size", EmptySlot, size, 0),
84     DEFINE_PROP_STRING("name", EmptySlot, name),
85     DEFINE_PROP_END_OF_LIST(),
86 };
87 
88 static void empty_slot_class_init(ObjectClass *klass, void *data)
89 {
90     DeviceClass *dc = DEVICE_CLASS(klass);
91 
92     dc->realize = empty_slot_realize;
93     device_class_set_props(dc, empty_slot_properties);
94     set_bit(DEVICE_CATEGORY_MISC, dc->categories);
95 }
96 
97 static const TypeInfo empty_slot_info = {
98     .name          = TYPE_EMPTY_SLOT,
99     .parent        = TYPE_SYS_BUS_DEVICE,
100     .instance_size = sizeof(EmptySlot),
101     .class_init    = empty_slot_class_init,
102 };
103 
104 static void empty_slot_register_types(void)
105 {
106     type_register_static(&empty_slot_info);
107 }
108 
109 type_init(empty_slot_register_types)
110