static void pcibios_allocate_bus_resources()

in pci/pci-common.c [667:736]

• 47 lines of code
• 18 McCabe index (conditional complexity)

static void pcibios_allocate_bus_resources(struct pci_bus *bus)
{
	struct pci_bus *b;
	int i;
	struct resource *res, *pr;

	pr_debug("PCI: Allocating bus resources for %04x:%02x...\n",
		 pci_domain_nr(bus), bus->number);

	pci_bus_for_each_resource(bus, res, i) {
		if (!res || !res->flags
		    || res->start > res->end || res->parent)
			continue;
		if (bus->parent == NULL)
			pr = (res->flags & IORESOURCE_IO) ?
				&ioport_resource : &iomem_resource;
		else {
			/* Don't bother with non-root busses when
			 * re-assigning all resources. We clear the
			 * resource flags as if they were colliding
			 * and as such ensure proper re-allocation
			 * later.
			 */
			pr = pci_find_parent_resource(bus->self, res);
			if (pr == res) {
				/* this happens when the generic PCI
				 * code (wrongly) decides that this
				 * bridge is transparent  -- paulus
				 */
				continue;
			}
		}

		pr_debug("PCI: %s (bus %d) bridge rsrc %d: %016llx-%016llx ",
			 bus->self ? pci_name(bus->self) : "PHB",
			 bus->number, i,
			 (unsigned long long)res->start,
			 (unsigned long long)res->end);
		pr_debug("[0x%x], parent %p (%s)\n",
			 (unsigned int)res->flags,
			 pr, (pr && pr->name) ? pr->name : "nil");

		if (pr && !(pr->flags & IORESOURCE_UNSET)) {
			struct pci_dev *dev = bus->self;

			if (request_resource(pr, res) == 0)
				continue;
			/*
			 * Must be a conflict with an existing entry.
			 * Move that entry (or entries) under the
			 * bridge resource and try again.
			 */
			if (reparent_resources(pr, res) == 0)
				continue;

			if (dev && i < PCI_BRIDGE_RESOURCE_NUM &&
			    pci_claim_bridge_resource(dev,
						 i + PCI_BRIDGE_RESOURCES) == 0)
				continue;

		}
		pr_warn("PCI: Cannot allocate resource region ");
		pr_cont("%d of PCI bridge %d, will remap\n", i, bus->number);
		res->start = res->end = 0;
		res->flags = 0;
	}

	list_for_each_entry(b, &bus->children, node)
		pcibios_allocate_bus_resources(b);
}