hw/misc/unimp.c

   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/hw.h"
  16 #include "hw/sysbus.h"
  17 #include "hw/misc/unimp.h"
  18 #include "qemu/log.h"
  19 #include "qemu/module.h"
  20 #include "qapi/error.h"
  21
  22 static uint64_t unimp_read(void *opaque, hwaddr offset, unsigned size)
  23 {
  24     UnimplementedDeviceState *s = UNIMPLEMENTED_DEVICE(opaque);
  25
  26     qemu_log_mask(LOG_UNIMP, "%s: unimplemented device read "
  27                   "(size %d, offset 0x%" HWADDR_PRIx ")\n",
  28                   s->name, size, offset);
  29     return 0;
  30 }
  31
  32 static void unimp_write(void *opaque, hwaddr offset,
  33                         uint64_t value, unsigned size)
  34 {
  35     UnimplementedDeviceState *s = UNIMPLEMENTED_DEVICE(opaque);
  36
  37     qemu_log_mask(LOG_UNIMP, "%s: unimplemented device write "
  38                   "(size %d, value 0x%" PRIx64
  39                   ", offset 0x%" HWADDR_PRIx ")\n",
  40                   s->name, size, value, offset);
  41 }
  42
  43 static const MemoryRegionOps unimp_ops = {
  44     .read = unimp_read,
  45     .write = unimp_write,
  46     .impl.min_access_size = 1,
  47     .impl.max_access_size = 8,
  48     .valid.min_access_size = 1,
  49     .valid.max_access_size = 8,
  50     .endianness = DEVICE_NATIVE_ENDIAN,
  51 };
  52
  53 static void unimp_realize(DeviceState *dev, Error **errp)
  54 {
  55     UnimplementedDeviceState *s = UNIMPLEMENTED_DEVICE(dev);
  56
  57     if (s->size == 0) {
  58         error_setg(errp, "property 'size' not specified or zero");
  59         return;
  60     }
  61
  62     if (s->name == NULL) {
  63         error_setg(errp, "property 'name' not specified");
  64         return;
  65     }
  66
  67     memory_region_init_io(&s->iomem, OBJECT(s), &unimp_ops, s,
  68                           s->name, s->size);
  69     sysbus_init_mmio(SYS_BUS_DEVICE(s), &s->iomem);
  70 }
  71
  72 static Property unimp_properties[] = {
  73     DEFINE_PROP_UINT64("size", UnimplementedDeviceState, size, 0),
  74     DEFINE_PROP_STRING("name", UnimplementedDeviceState, name),
  75     DEFINE_PROP_END_OF_LIST(),
  76 };
  77
  78 static void unimp_class_init(ObjectClass *klass, void *data)
  79 {
  80     DeviceClass *dc = DEVICE_CLASS(klass);
  81
  82     dc->realize = unimp_realize;
  83     dc->props = unimp_properties;
  84 }
  85
  86 static const TypeInfo unimp_info = {
  87     .name = TYPE_UNIMPLEMENTED_DEVICE,
  88     .parent = TYPE_SYS_BUS_DEVICE,
  89     .instance_size = sizeof(UnimplementedDeviceState),
  90     .class_init = unimp_class_init,
  91 };
  92
  93 static void unimp_register_types(void)
  94 {
  95     type_register_static(&unimp_info);
  96 }
  97
  98 type_init(unimp_register_types)