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 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%" HWADDR_PRIx ")\n",
  27                   s->name, size, offset);
  28     return 0;
  29 }
  30
  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, value 0x%" PRIx64
  38                   ", offset 0x%" HWADDR_PRIx ")\n",
  39                   s->name, size, value, offset);
  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
  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     memory_region_init_io(&s->iomem, OBJECT(s), &unimp_ops, s,
  67                           s->name, s->size);
  68     sysbus_init_mmio(SYS_BUS_DEVICE(s), &s->iomem);
  69 }
  70
  71 static Property unimp_properties[] = {
  72     DEFINE_PROP_UINT64("size", UnimplementedDeviceState, size, 0),
  73     DEFINE_PROP_STRING("name", UnimplementedDeviceState, name),
  74     DEFINE_PROP_END_OF_LIST(),
  75 };
  76
  77 static void unimp_class_init(ObjectClass *klass, void *data)
  78 {
  79     DeviceClass *dc = DEVICE_CLASS(klass);
  80
  81     dc->realize = unimp_realize;
  82     dc->props = unimp_properties;
  83 }
  84
  85 static const TypeInfo unimp_info = {
  86     .name = TYPE_UNIMPLEMENTED_DEVICE,
  87     .parent = TYPE_SYS_BUS_DEVICE,
  88     .instance_size = sizeof(UnimplementedDeviceState),
  89     .class_init = unimp_class_init,
  90 };
  91
  92 static void unimp_register_types(void)
  93 {
  94     type_register_static(&unimp_info);
  95 }
  96
  97 type_init(unimp_register_types)