1 /* "Unimplemented" device
2 *
3 * This is a dummy device which accepts and logs all accesses.
4 * It's useful for stubbing out regions of an SoC or board
5 * map which correspond to devices that have not yet been
6 * implemented. This is often sufficient to placate initial
7 * guest device driver probing such that the system will
8 * come up.
9 *
10 * Copyright Linaro Limited, 2017
11 * Written by Peter Maydell
12 */
13
14 #include "qemu/osdep.h"
15 #include "hw/sysbus.h"
16 #include "hw/misc/unimp.h"
17 #include "qemu/log.h"
18 #include "qemu/module.h"
19 #include "qapi/error.h"
20
unimp_read(void * opaque,hwaddr offset,unsigned size)21 static uint64_t unimp_read(void *opaque, hwaddr offset, unsigned size)
22 {
23 UnimplementedDeviceState *s = UNIMPLEMENTED_DEVICE(opaque);
24
25 qemu_log_mask(LOG_UNIMP, "%s: unimplemented device read "
26 "(size %d, offset 0x%0*" HWADDR_PRIx ")\n",
27 s->name, size, s->offset_fmt_width, offset);
28 return 0;
29 }
30
unimp_write(void * opaque,hwaddr offset,uint64_t value,unsigned size)31 static void unimp_write(void *opaque, hwaddr offset,
32 uint64_t value, unsigned size)
33 {
34 UnimplementedDeviceState *s = UNIMPLEMENTED_DEVICE(opaque);
35
36 qemu_log_mask(LOG_UNIMP, "%s: unimplemented device write "
37 "(size %d, offset 0x%0*" HWADDR_PRIx
38 ", value 0x%0*" PRIx64 ")\n",
39 s->name, size, s->offset_fmt_width, offset, size << 1, value);
40 }
41
42 static const MemoryRegionOps unimp_ops = {
43 .read = unimp_read,
44 .write = unimp_write,
45 .impl.min_access_size = 1,
46 .impl.max_access_size = 8,
47 .valid.min_access_size = 1,
48 .valid.max_access_size = 8,
49 .endianness = DEVICE_NATIVE_ENDIAN,
50 };
51
unimp_realize(DeviceState * dev,Error ** errp)52 static void unimp_realize(DeviceState *dev, Error **errp)
53 {
54 UnimplementedDeviceState *s = UNIMPLEMENTED_DEVICE(dev);
55
56 if (s->size == 0) {
57 error_setg(errp, "property 'size' not specified or zero");
58 return;
59 }
60
61 if (s->name == NULL) {
62 error_setg(errp, "property 'name' not specified");
63 return;
64 }
65
66 s->offset_fmt_width = DIV_ROUND_UP(64 - clz64(s->size - 1), 4);
67
68 memory_region_init_io(&s->iomem, OBJECT(s), &unimp_ops, s,
69 s->name, s->size);
70 sysbus_init_mmio(SYS_BUS_DEVICE(s), &s->iomem);
71 }
72
73 static Property unimp_properties[] = {
74 DEFINE_PROP_UINT64("size", UnimplementedDeviceState, size, 0),
75 DEFINE_PROP_STRING("name", UnimplementedDeviceState, name),
76 DEFINE_PROP_END_OF_LIST(),
77 };
78
unimp_class_init(ObjectClass * klass,void * data)79 static void unimp_class_init(ObjectClass *klass, void *data)
80 {
81 DeviceClass *dc = DEVICE_CLASS(klass);
82
83 dc->realize = unimp_realize;
84 device_class_set_props(dc, unimp_properties);
85 }
86
87 static const TypeInfo unimp_info = {
88 .name = TYPE_UNIMPLEMENTED_DEVICE,
89 .parent = TYPE_SYS_BUS_DEVICE,
90 .instance_size = sizeof(UnimplementedDeviceState),
91 .class_init = unimp_class_init,
92 };
93
unimp_register_types(void)94 static void unimp_register_types(void)
95 {
96 type_register_static(&unimp_info);
97 }
98
99 type_init(unimp_register_types)
100