On 01/31/2012 08:51 AM, Jan Kiszka wrote:
On 2012-01-31 15:47, Anthony Liguori wrote:
On 01/31/2012 08:34 AM, Jan Kiszka wrote:
On 2012-01-26 20:00, Anthony Liguori wrote:
@@ -548,6 +550,13 @@ static int piix3_realize(PCIDevice *dev)
       /* Setup the RTC IRQ */
       s->rtc.irq = rtc_irq;

+    /* Realize the PIT */
+    qdev_set_parent_bus(DEVICE(&s->pit), BUS(s->bus));
+    qdev_init_nofail(DEVICE(&s->pit));
+
+    /* FIXME this should be refactored */
+    pcspk_init(ISA_DEVICE(&s->pit));

Fixing ATM, ie. converting to qdev/QOM.

Q: How do I use qdev_property_add_link&   Co. to establish the relation
from the speaker port device to the PIT?

In the state structure, have:

struct PCSpkState {
      ...
      PITState *pit;
};

In the pcspk instance_init, do:

object_property_add_link(obj, "pit", TYPE_PIT, (Object **)&s->pit, NULL);

In the pcspk realize function (DeviceClass::init), do:

assert(s->pit != NULL); // make sure the pit link is set

And that's it.

You can set the s->pit field directly.  You are not required to use any special
QOM function to interact with link properties.

BTW, this is yet another benefit of making structures public.  You can take the
address of a child and set link fields directly without accessors.

Well, that has two sides. We introduced properties to avoid this direct
messing.

Does linking also work without exposing internals?

Yes, you can set links through properties (although I haven't added those accessors yet).

But... you lose type safety because now you're dealing with strings. If we want to avoid exposing internals, we should provide accessors to get/set links. So:

typedef struct PCSpkState PCSpkState;

void pcspk_set_pit(PCSpkState *s, PITState *pit);

Regards,

Anthony Liguori


Jan



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