Peter Maydell <peter.mayd...@linaro.org> writes: > On 17 October 2013 14:54, <arm...@redhat.com> wrote: >> From: Markus Armbruster <arm...@redhat.com> >> >> Many PCI host bridges consist of a sysbus device and a PCI device. >> You need both for the thing to work. Arguably, these bridges should >> be modelled as a single, composite devices instead of pairs of >> seemingly independent devices you can only use together, but we're not >> there, yet. > > I disagree here -- we should be using the modularity that our > device model provides, not arbitrarily squashing things together > into single objects just because we've foolishly exposed to the > end user direct command line access to "create any random object > whatsoever even if it doesn't make sense".
I'm afraid I didn't express myself clearly. I'm not advocating *squashing* these components together. I'm saying that if A and B can only be used wired together, there should be a C composed of A, B and the necessary wiring, and that C is what actually gets put on the board by configuration. >> Since the sysbus part can't be instantiated with device_add, yet, >> permitting it with the PCI part is useless. We shouldn't offer >> useless options to the user, so let's set >> cannot_instantiate_with_device_add_yet for them. > > It doesn't make sense to allow the user to create the on-PCI-bus > representation of the host controller anyway even if they could > device_add the host controller proper: creating the host controller > will always automatically create the on-PCI-bus part. Technically, a device_add i440FX-pcihost doesn't automatically create i440FX *now*. I suspect we're arguing only about what exact kind of crazy device_add of the PCI-facing part of the PCI host bridge is. Assuming we actually agree it's crazy in *today's* state of things, does it matter what kind of crazy it is? If it doesn't matter, perhaps you could give me a hint on how to rephrase the commit message. >> --- a/hw/mips/gt64xxx_pci.c >> +++ b/hw/mips/gt64xxx_pci.c >> @@ -1157,6 +1157,11 @@ static void >> gt64120_pci_class_init(ObjectClass *klass, void *data) >> k->device_id = PCI_DEVICE_ID_MARVELL_GT6412X; >> k->revision = 0x10; >> k->class_id = PCI_CLASS_BRIDGE_HOST; >> + /* >> + * PCI-facing part of the host bridge, not usable without the >> + * host-facing part, which can't be device_add'ed, yet. >> + */ >> + k->parent_class.cannot_instantiate_with_device_add_yet = true; > > Please don't directly access parent_class -- you should be using > the proper QOM cast macros to get the DeviceClass pointer. Will fix, thanks!
