xref: /openbmc/qemu/hw/misc/empty_slot.c (revision 8fa3b702)
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 typedef struct EmptySlot EmptySlot;
22 DECLARE_INSTANCE_CHECKER(EmptySlot, EMPTY_SLOT,
23                          TYPE_EMPTY_SLOT)
24 
25 struct EmptySlot {
26     SysBusDevice parent_obj;
27 
28     MemoryRegion iomem;
29     char *name;
30     uint64_t size;
31 };
32 
33 static uint64_t empty_slot_read(void *opaque, hwaddr addr,
34                                 unsigned size)
35 {
36     EmptySlot *s = EMPTY_SLOT(opaque);
37 
38     trace_empty_slot_write(addr, size << 1, 0, size, s->name);
39 
40     return 0;
41 }
42 
43 static void empty_slot_write(void *opaque, hwaddr addr,
44                              uint64_t val, unsigned size)
45 {
46     EmptySlot *s = EMPTY_SLOT(opaque);
47 
48     trace_empty_slot_write(addr, size << 1, val, size, s->name);
49 }
50 
51 static const MemoryRegionOps empty_slot_ops = {
52     .read = empty_slot_read,
53     .write = empty_slot_write,
54     .endianness = DEVICE_NATIVE_ENDIAN,
55 };
56 
57 void empty_slot_init(const char *name, hwaddr addr, uint64_t slot_size)
58 {
59     if (slot_size > 0) {
60         /* Only empty slots larger than 0 byte need handling. */
61         DeviceState *dev;
62 
63         dev = qdev_new(TYPE_EMPTY_SLOT);
64 
65         qdev_prop_set_uint64(dev, "size", slot_size);
66         sysbus_realize_and_unref(SYS_BUS_DEVICE(dev), &error_fatal);
67 
68         sysbus_mmio_map_overlap(SYS_BUS_DEVICE(dev), 0, addr, -10000);
69     }
70 }
71 
72 static void empty_slot_realize(DeviceState *dev, Error **errp)
73 {
74     EmptySlot *s = EMPTY_SLOT(dev);
75 
76     if (s->name == NULL) {
77         s->name = g_strdup("empty-slot");
78     }
79     memory_region_init_io(&s->iomem, OBJECT(s), &empty_slot_ops, s,
80                           s->name, s->size);
81     sysbus_init_mmio(SYS_BUS_DEVICE(dev), &s->iomem);
82 }
83 
84 static Property empty_slot_properties[] = {
85     DEFINE_PROP_UINT64("size", EmptySlot, size, 0),
86     DEFINE_PROP_STRING("name", EmptySlot, name),
87     DEFINE_PROP_END_OF_LIST(),
88 };
89 
90 static void empty_slot_class_init(ObjectClass *klass, void *data)
91 {
92     DeviceClass *dc = DEVICE_CLASS(klass);
93 
94     dc->realize = empty_slot_realize;
95     device_class_set_props(dc, empty_slot_properties);
96     set_bit(DEVICE_CATEGORY_MISC, dc->categories);
97 }
98 
99 static const TypeInfo empty_slot_info = {
100     .name          = TYPE_EMPTY_SLOT,
101     .parent        = TYPE_SYS_BUS_DEVICE,
102     .instance_size = sizeof(EmptySlot),
103     .class_init    = empty_slot_class_init,
104 };
105 
106 static void empty_slot_register_types(void)
107 {
108     type_register_static(&empty_slot_info);
109 }
110 
111 type_init(empty_slot_register_types)
112