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 "qapi/error.h"
  20
  21 #define UNIMPLEMENTED_DEVICE(obj) \
  22     OBJECT_CHECK(UnimplementedDeviceState, (obj), TYPE_UNIMPLEMENTED_DEVICE)
  23
  24 typedef struct {
  25     SysBusDevice parent_obj;
  26     MemoryRegion iomem;
  27     char *name;
  28     uint64_t size;
  29 } UnimplementedDeviceState;
  30
  31 static uint64_t unimp_read(void *opaque, hwaddr offset, unsigned size)
  32 {
  33     UnimplementedDeviceState *s = UNIMPLEMENTED_DEVICE(opaque);
  34
  35     qemu_log_mask(LOG_UNIMP, "%s: unimplemented device read "
  36                   "(size %d, offset 0x%" HWADDR_PRIx ")\n",
  37                   s->name, size, offset);
  38     return 0;
  39 }
  40
  41 static void unimp_write(void *opaque, hwaddr offset,
  42                         uint64_t value, unsigned size)
  43 {
  44     UnimplementedDeviceState *s = UNIMPLEMENTED_DEVICE(opaque);
  45
  46     qemu_log_mask(LOG_UNIMP, "%s: unimplemented device write "
  47                   "(size %d, value 0x%" PRIx64
  48                   ", offset 0x%" HWADDR_PRIx ")\n",
  49                   s->name, size, value, offset);
  50 }
  51
  52 static const MemoryRegionOps unimp_ops = {
  53     .read = unimp_read,
  54     .write = unimp_write,
  55     .impl.min_access_size = 1,
  56     .impl.max_access_size = 8,
  57     .valid.min_access_size = 1,
  58     .valid.max_access_size = 8,
  59     .endianness = DEVICE_NATIVE_ENDIAN,
  60 };
  61
  62 static void unimp_realize(DeviceState *dev, Error **errp)
  63 {
  64     UnimplementedDeviceState *s = UNIMPLEMENTED_DEVICE(dev);
  65
  66     if (s->size == 0) {
  67         error_setg(errp, "property 'size' not specified or zero");
  68         return;
  69     }
  70
  71     if (s->name == NULL) {
  72         error_setg(errp, "property 'name' not specified");
  73         return;
  74     }
  75
  76     memory_region_init_io(&s->iomem, OBJECT(s), &unimp_ops, s,
  77                           s->name, s->size);
  78     sysbus_init_mmio(SYS_BUS_DEVICE(s), &s->iomem);
  79 }
  80
  81 static Property unimp_properties[] = {
  82     DEFINE_PROP_UINT64("size", UnimplementedDeviceState, size, 0),
  83     DEFINE_PROP_STRING("name", UnimplementedDeviceState, name),
  84     DEFINE_PROP_END_OF_LIST(),
  85 };
  86
  87 static void unimp_class_init(ObjectClass *klass, void *data)
  88 {
  89     DeviceClass *dc = DEVICE_CLASS(klass);
  90
  91     dc->realize = unimp_realize;
  92     dc->props = unimp_properties;
  93 }
  94
  95 static const TypeInfo unimp_info = {
  96     .name = TYPE_UNIMPLEMENTED_DEVICE,
  97     .parent = TYPE_SYS_BUS_DEVICE,
  98     .instance_size = sizeof(UnimplementedDeviceState),
  99     .class_init = unimp_class_init,
 100 };
 101
 102 static void unimp_register_types(void)
 103 {
 104     type_register_static(&unimp_info);
 105 }
 106
 107 type_init(unimp_register_types)