PLEASE REVIEW: Adding a pci_if method to facilitate specialized PCI bus drivers

[Thomas Moestl]

On Fri, 2003/06/27 at 14:01:45 -0400, John Baldwin wrote:
> On 27-Jun-2003 Thomas Moestl wrote:
> > On Fri, 2003/06/27 at 13:37:00 -0400, John Baldwin wrote:
> >> On 13-Jun-2003 Thomas Moestl wrote:
> >> > This requires us to get this firmware property in the OFW PCI bus
> >> > driver before routing the interrupt; that can't be done in the pcib
> >> > route_interrupt method, since we don't know whether we are routing for
> >> > another bridge (where we use whichever index we get passed) or for a
> >> > child device (in which case we would need to look at the firmware
> >> > property).
> >> 
> >> Actually, can't you tell this by doing:
> >> 
> >>         if (device_get_parent(device_get_parent(dev)) == pcib)
> >>                 /* Routing direct child. */
> >>         else
> >>                 /* Routing descedent of a child bridge. */
> > 
> > No, pcib will always be a grandparent of dev. When routing a
							      ^ for 
> > descendant child bridge, dev will itself be the device_t of a bridge,
              ^ of a (oops)
> > otherwise it is that of the device we are routing to.
> Doh, yes. :(  Hmm, can you try something like this maybe:
> 
>         if (pci_get_class(dev) == PCIC_BRIDGE &&
>             pci_get_subclass(dev) == PCIS_BRIDGE_PCI)
>                 /* Routing across a child bridge. */
>         else
>                 /* Routing a direct child that is not a bridge. */

This leaves two possible problems: first, there are other types of
bridges (we currently support PCI-ISA and PCI-EBus ones, cardbus might
also work) for which we need to use PCIB_ROUTE_INTERRUPT(); that could
likely be dealt with by not testing the subclass at all.
More importantly, however, a bridge might want to allocate an
interrupt for itself; for example, cardbus bridge drivers do this to
handle insertion/ejection/etc events.

I think that handling this at the bus driver level is a much cleaner
solution.

	- Thomas

-- 
Thomas Moestl <t.moestl at tu-bs.de>	http://www.tu-bs.de/~y0015675/
              <tmm at FreeBSD.org>		http://people.FreeBSD.org/~tmm/
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