PCI/ACPI: Extend pci_mcfg_lookup() to return ECAM config accessors

pci_mcfg_lookup() is the external interface to the generic MCFG code.
Previously it merely looked up the ECAM base address for a given domain and
bus range.  We want a way to add MCFG quirks, some of which may require
special config accessors and adjustments to the ECAM address range.

Extend pci_mcfg_lookup() so it can return a pointer to a pci_ecam_ops
structure and a struct resource for the ECAM address space.  For now, it
always returns &pci_generic_ecam_ops (the standard accessor) and the
resource described by the MCFG.

No functional changes intended.

[bhelgaas: changelog]
Signed-off-by: Tomasz Nowicki <tn@semihalf.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
diff --git a/include/linux/pci-acpi.h b/include/linux/pci-acpi.h
index 7d63a66..7a4e83a 100644
--- a/include/linux/pci-acpi.h
+++ b/include/linux/pci-acpi.h
@@ -24,7 +24,9 @@ static inline acpi_status pci_acpi_remove_pm_notifier(struct acpi_device *dev)
 }
 extern phys_addr_t acpi_pci_root_get_mcfg_addr(acpi_handle handle);
 
-extern phys_addr_t pci_mcfg_lookup(u16 domain, struct resource *bus_res);
+struct pci_ecam_ops;
+extern int pci_mcfg_lookup(struct acpi_pci_root *root, struct resource *cfgres,
+			   struct pci_ecam_ops **ecam_ops);
 
 static inline acpi_handle acpi_find_root_bridge_handle(struct pci_dev *pdev)
 {