Use bus multipass for interrupt controllers on PowerPC

[nwhitehorn]

Summary

This adjusts all PPC interrupt controllers to attach at BUS_PASS_INTERRUPT and all potential parent buses to attach at BUS_PASS_BUS. Where parent devices and interrupt controllers need to set up interrupts on interrupt controllers, delay interrupt setup until after BUS_PASS_INTERRUPT has finished using a bus_new_pass() hook. This will eventually allow us to turn off the hope-for-the-best interrupt preallocation code in powerpc/intr_machdep.c.

Test Plan

Tested only on a G5 powermac so far.

[nwhitehorn]

Note: This partially implements the changes in D918.

[nwhitehorn]

Fix unused variable and make patch relative to src/ rather than src/sys.

[nwhitehorn]

Fix missing file.

[nwhitehorn]

Actually update the diff, since I still forgot that file last time.

[jhb]

In general I think this looks fine. I do think it's probably simpler to just defer all of the interrupt-related bits (including bus_alloc_resource()). You could imagine systems that create IRQ resources in a BUS_PASS_INTERRUPT driver that won't be available to allocate prior to that. I also think it's a bit cleaner to have a separate routine when deferring the IRQ allocation/setup that is called from bus_new_pass. Eventually we may also do something similar with SYS_RES_IOPORT/SYS_RES_MEMORY resources being deferred until after BUS_PASS_RESOURCE. Having bus_new_pass methods that just call various helper routines based on pass number will be clearer in that case I think than moving all the logic into the bus_new_pass callback.

I have a mild preference for committing the MI drivers as a separate change first, but it's also fine as one change since people on non-powerpc can still bisect the entire revision effectively.

sys/dev/pci/pci_pci.c

1350

I would perhaps call this 'pcib_pcie_alloc_irq()' and have pcib_pcie_new_pass() be something like:

static void
pcib_pcie_new_pass(device_t dev)
{

    if (bus_current_pass > BUS_PASS_INTERRUPT + BUS_PASS_ORDER_LAST)
        pcib_pcie_alloc_irq(dev);
    bus_generic_new_pass(dev);
}

1386–1390

Ah, I would actually defer all of pcib_pcie_alloc_irq() (including all the MSI song and dance) in which case you won't need this change or the explicit bus_activate_resource(). (Missed that part of the change in the comment above). That would then let you still have a "simple" bus_new_pass method that just calls pcib_pcie_alloc_irq() if need be.