pci_pci: Support growing bus ranges in bus_adjust_resource for NEW_PCIB
This is the same underlying problem as 2624598064
, just for bus ranges
rather than windows. SiFive's HiFive Unmatched has the following
topology:
Root Port <---> Bridge <---> Bridge <-+-> Bridge <---> (Unused)
(pcib0) (pcib1) (pcib2) | (pcib3)
+-> Bridge <---> xHCI
| (pcib4)
+-> Bridge <---> M.2 E-key
| (pcib5)
+-> Bridge <---> M.2 M-key
| (pcib6)
+-> Bridge <---> x16 slot
(pcib7)
If a device is plugged into the x16 slot that itself has a bridge, such
as many graphics cards, we currently fail to allocate a bus number for
its child bus (and so pcib_attach_child skips adding a child bus for
further enumeration) as, when the new child bridge attaches, it attempts
to allocate a bus number from its parent (pcib7) which in turn attempts
to grow its own bus range by calling bus_adjust_resource on its own
parent (pcib2) whose bus rman cannot accommodate the request and needs
to itself be extended by calling its own parent (pcib1). Note that
pcib3-7 do not face the same issue when they attach since pcib1 ends up
managing bus numbers 1-255 from the beginning and so never needs to grow
its own range.
Reviewed by: jhb, mav
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D32011
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parent
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commit
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@ -2364,7 +2364,20 @@ pcib_adjust_resource(device_t bus, device_t child, int type, struct resource *r,
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start, end));
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#ifdef PCI_RES_BUS
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if (type != PCI_RES_BUS)
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if (type == PCI_RES_BUS) {
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/*
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* If our bus range isn't big enough to grow the sub-allocation
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* then we need to grow our bus range. Any request that would
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* require us to decrease the start of our own bus range is
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* invalid, we can only extend the end; ignore such requests
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* and let rman_adjust_resource fail below.
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*/
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if (start >= sc->bus.sec && end > sc->bus.sub) {
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error = pcib_grow_subbus(&sc->bus, end);
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if (error != 0)
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return (error);
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}
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} else
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#endif
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{
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/*
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