Re: [Qemu-devel] [PATCH 5/5] mc146818rtc: add "rtc" link to "/machine"

[Peter Crosthwaite]

On Thu, Jun 12, 2014 at 2:49 AM, Paolo Bonzini <address@hidden> wrote:
> From: Marcelo Tosatti <address@hidden>
>
> Add a link to rtc under /machine providing a stable
> location for management apps to query "date" field.
>
> {"execute":"qom-get","arguments":{"path":"/machine/rtc","property":"date"} }
>
> Suggested by Paolo Bonzini.
>
> Signed-off-by: Marcelo Tosatti <address@hidden>
> Signed-off-by: Paolo Bonzini <address@hidden>
> Signed-off-by: address@hidden <address@hidden>
> ---
>  hw/timer/mc146818rtc.c | 9 +++++++++
>  1 file changed, 9 insertions(+)
>
> diff --git a/hw/timer/mc146818rtc.c b/hw/timer/mc146818rtc.c
> index df54546..8c706e1 100644
> --- a/hw/timer/mc146818rtc.c
> +++ b/hw/timer/mc146818rtc.c
> @@ -893,6 +893,9 @@ static void rtc_realizefn(DeviceState *dev, Error **errp)
>
>      object_property_add(OBJECT(s), "date", "struct tm",
>                          rtc_get_date, NULL, NULL, s, NULL);
> +
> +    object_property_add_alias(qdev_get_machine(), "rtc",
> +                              OBJECT(s), NULL, &error_abort);

This will fail if anyone wants to add two such devices to a machine
model. It seems a bit board specific to assume that this device is
only valid as a singleton. Perhaps s/&error_abort/local_err/ and
raising a warning explaining that only the first RTC in the system
gets the alias?

The other options is arrayification using your (hot off the press)
"[*]" proposal:

+    object_property_add_alias(qdev_get_machine(), "rtc[*]",
+                              OBJECT(s), NULL, &error_abort);

Regards,
Peter

>  }
>
>  ISADevice *rtc_init(ISABus *bus, int base_year, qemu_irq intercept_irq)
> @@ -932,11 +935,17 @@ static void rtc_class_initfn(ObjectClass *klass, void 
> *data)
>      dc->cannot_instantiate_with_device_add_yet = true;
>  }
>
> +static void rtc_finalize(Object *obj)
> +{
> +    object_property_del(qdev_get_machine(), "rtc", NULL);
> +}
> +
>  static const TypeInfo mc146818rtc_info = {
>      .name          = TYPE_MC146818_RTC,
>      .parent        = TYPE_ISA_DEVICE,
>      .instance_size = sizeof(RTCState),
>      .class_init    = rtc_class_initfn,
> +    .instance_finalize = rtc_finalize,
>  };
>
>  static void mc146818rtc_register_types(void)
> --
> 1.8.3.1
>
>