Gleb Natapov <g...@redhat.com> writes:
> On Mon, Oct 25, 2010 at 06:22:12PM +0200, Markus Armbruster wrote:
>> Gleb Natapov <g...@redhat.com> writes:
>>
>> > On Mon, Oct 25, 2010 at 04:29:35PM +0200, Markus Armbruster wrote:
>> >> Gleb Natapov <g...@redhat.com> writes:
>> >>
>> >> > Without this patch both buses on PIIX3_IDE device have the same unit id.
>> >>
>> >> Are you sure that's wrong?
>> >>
>> > So how do I know which bus is it on PIIX3_IDE?
>> [...]
>>
>> Let me try to explain the IDE pointer thicket.
>>
>> piix3-ide provides two IDE buses. pci_piix_ide_initfn() stores them in
>> PCIIDEState member IDEBus bus[2]. Technically redundant, because qdev
>> stores child buses in dev.qdev.child_bus.
>>
>> IDEBus points back: qbus.parent.
>>
>> Up to two IDE devices can sit on each IDE bus. The first one uses
>> IDEBus members master and ifs[0], the second one uses slave and ifs[1].
>>
>> ifs[i].bus points back to the IDE bus.
>>
>> {master,slave}.qdev.parent_bus point back to the IDE bus.
>>
>> Say you got an IDEDevice and want to know which to which of the two
>> buses it's connected. Let's call it d.
>>
>> d->qdev.parent_bus is the BusState.
>>
>> Upcast to IDEBus: b = DO_UPCAST(IDEBus, qbus, d->qdev.parent_bus).
>>
>> b->qbus.parent is the IDE controller.
>>
>> Upcast to PCIIDEState: c = DO_UPCAST(PCIIDEState, dev, n->qbus.parent);
>>
> This will not work if IDEBus sits on ISA bus. Any other ideas?
>
>> If c->bus[0] == b, it's on the first bus.
>>
>> Else it must be on the second bus, i.e. c->bus[1] == b.
Well, you asked for piix3-ide specifically :)
isa-ide provides just one IDE bus. Thus we have two isa-ide devices.
To find them, you need to walk the ISA devices. Our PCish machines have
just one ISA bus, and it's called "isa.0". You could try
bus = qbus_find("isa.0");
QLIST_FOREACH(dev, &bus->children, sibling) {
// examine dev
// it's safe to upcast dev to ISADevice
}
Perhaps best to have some means in qdev.h to iterate over a bus like
that.
If dev->info->name is "isa-ide", you found one of the controllers.
How to tell whether it's primary or secondary? Primary uses I/O ports
0x1f0..0x1ff,0x3f0..0x3ff and IRQ 14. IRQ could be easier to check,
because it should be right in ISADevice member isairq[0].
Alternatively, upcast to ISAIDEState and check members iobase or isairq.
Hmm, there's a way that doesn't require special-casing the IDE
controller devices: find the IDEBus as above. Then check the IRQ#
b->irq->n: 14 is primary, 15 is secondary.
