From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([140.186.70.92]:36859) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1RsF8U-0003jc-Mp for qemu-devel@nongnu.org; Tue, 31 Jan 2012 09:56:48 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1RsF8P-000738-DM for qemu-devel@nongnu.org; Tue, 31 Jan 2012 09:56:42 -0500 Received: from mail-pz0-f45.google.com ([209.85.210.45]:64730) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1RsF8P-00072y-7I for qemu-devel@nongnu.org; Tue, 31 Jan 2012 09:56:37 -0500 Received: by dadp14 with SMTP id p14so22810dad.4 for ; Tue, 31 Jan 2012 06:56:36 -0800 (PST) Message-ID: <4F280120.2070402@codemonkey.ws> Date: Tue, 31 Jan 2012 08:56:32 -0600 From: Anthony Liguori MIME-Version: 1.0 References: <1327604460-31142-1-git-send-email-aliguori@us.ibm.com> <1327604460-31142-7-git-send-email-aliguori@us.ibm.com> <4F27FBE6.7040800@siemens.com> <4F27FEFD.5070507@codemonkey.ws> <4F28000B.5060406@siemens.com> In-Reply-To: <4F28000B.5060406@siemens.com> Content-Type: text/plain; charset=ISO-8859-15; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH 06/15] piix: create i8254 through composition List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Jan Kiszka Cc: Peter Maydell , Anthony Liguori , "qemu-devel@nongnu.org" , Markus Armbruster , Avi Kivity , Paolo Bonzini 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 >